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Trees enhance life in a multitude of ways. They combat climate change by reducing greenhouse gases in the atmosphere. They muffle sound pollution and reduce air pollution, drawing in carbon dioxide and releasing oxygen. When rain pours from the skies, trees decrease stormwater runoff, preventing flooding and soil erosion. They also provide valuable habitats to support biodiversity in insects, birds, and other animals, and microorganisms. The list goes on.

Equally important is accumulating evidence that simply spending time around trees and green spaces uplifts our health and mood. Below are a few of the biggest benefits we reap.

Keeping it cool: Trees help prevent heat-related illness

Climate change is causing rising temperatures and more heat waves across the US. These effects are worse for those who live in neighborhoods known as urban heat islands, where asphalt and concrete soak up heat during the day and continue to radiate it at night. Temperatures can reach 7° F hotter than suburban, rural, or simply wealthier and leafier neighborhoods.

Trees and their leafy canopy provide shade that helps to prevent urban heat islands. What does that mean for individuals? It translates to fewer heat-related health illnesses, which strike outdoor workers and younger, older, and medically vulnerable people more often. A study published in The Lancet calculated that increasing tree canopy to 30% coverage in 93 European cities could prevent an estimated four in 10 premature heat-related deaths in adults in those cities.

How trees help children: Better mood, behavior, attention, and more

Spending more time in nature has been linked with better health outcomes like lower blood pressure, better sleep, and improvement in many chronic conditions in adults. These findings are prompting a growing interest in forest therapy, a guided outdoor healing practice that leads to overall improved well-being. But what’s also remarkable are the varied benefits of trees and nature for children.

One study of children 4 to 6 years old found that those who lived close to green space demonstrated less hyperactive behavior and scored more highly on attention and visual memory testing measures compared with children who did not.

Just seeing trees can have mental health benefits. In Michigan, a study of children between the ages of 7 and 9 demonstrated that students who could see trees from their school windows had fewer behavioral problems than those with limited views.

In Finland, researchers modified daycare outdoor playscape environments to mimic the forest undergrowth. These daycares were compared to control standard daycares and nature-oriented daycares where children made daily visits to nearby forests. At the end of 28 days, the children in the daycares with modified forest undergrowth playscapes harbored a healthier microbiome and had improved markers of their immune systems as compared to their counterparts.

How green space helps communities

Having green space in neighborhoods also does a lot to enrich the well-being of communities. A randomized trial in a US city planted and maintained grass and trees in previously vacant lots. Researchers then compared these green spaces to lots that were left alone.

In neighborhoods below the poverty line, there was a reduction in crime for areas with greened lots compared to untouched vacant lots. Meanwhile, residents who lived near lots that were greened reported feeling safer and increased their use of the outside space for relaxing and socializing.

How can you help?

Unfortunately, urban tree canopy cover has been declining over the years. To counter this decline, many towns and nonprofit organizations have programs that provide trees for planting.

A few examples in Massachusetts are Canopy Crew in Cambridge and Speak for the Trees in Boston. (Speak for the Trees also offers helpful information on selecting and caring for trees). Neighborhood Forest provides trees for schools and other youth organizations across the US. Look for a program near you!

Planting trees native to your region will better suit the local conditions, wildlife, and ecosystem. Contact your regional Native Plant Society for more information and guidance. If you are worried about seasonal allergies from tree pollen, many tree organizations or certified arborists can give you guidance on the best native tree selections.

If planting trees is not for you but you are interested in contributing to the mission, consider donating to organizations that support reforestation, like The Canopy Project and the Arbor Day Foundation.

About the Author

Wynne Armand, MD, Contributor

Dr. Wynne Armand is a physician at Massachusetts General Hospital (MGH), where she provides primary care; an assistant professor in medicine at Harvard Medical School; and associate director of the MGH Center for the Environment and … See Full Bio View all posts by Wynne Armand, MD

Not so long ago, a friend texted me from a coffee shop. He said, "I can't believe it. I'm the only one here without a tattoo!" That might not seem surprising: a quick glance around practically anywhere people gather shows that tattoos are widely popular.

Nearly one-third of adults in the US have a tattoo, according to a Pew Research Center survey, including more than half of women ages 18 to 49. These numbers have increased dramatically over the last 20 years: around 21% of US adults in 2012 and 16% of adults in 2003 reported having at least one tattoo.

If you're among them, some recent headlines may have you worried:

              Study Finds That Tattoos Can Increase Your Risk of Lymphoma (OnlyMyHealth)

              Getting a Tattoo Puts You At Higher Risk of Cancer, Claims Study (NDTV)

              Inky waters: Tattoos increase risk of lymphoma by over 20%, study says (Local12.com)

              Shocking study reveals tattoos may increase risk of lymphoma by 20% (Fox News)

What study are they talking about? And how concerned should you be? Let's go through it together. One thing is clear: there's much more to this story than the headlines.

Why are researchers studying a possible link between tattoos and lymphoma?

Lymphoma is a type of cancer that starts in the lymphatic system, a network of vessels and lymph nodes that twines throughout the body. With about 90,000 newly diagnosed cases a year, lymphoma is one of the most common types of cancer.

Risk factors for it include:

• advancing age
• certain infections (such as Epstein-Barr virus, HIV, and hepatitis C)
• exposure to certain chemicals (such as benzene, or possibly pesticides)
• family history of lymphoma
• exposure to radiation (such as nuclear reactor accidents or after radiation therapy)
• having an impaired immune system
• certain immune diseases (such as rheumatoid arthritis, Sjogren's disease, or celiac disease).

Tattoos are not known to be a cause or risk factor for lymphoma. But there are several reasons to wonder if there might be a connection:

• Ink injected under the skin to create a tattoo contains several chemicals classified as carcinogenic (cancer causing).
• Pigment from tattoo ink can be found in enlarged lymph nodes within weeks of getting a tattoo.
• Immune cells in the skin can react to the chemicals in tattoo ink and travel to nearby lymph nodes, triggering a bodywide immune reaction.
• Other triggers of lymphoma, such as pesticides, have a similar effect on immune cells in lymph nodes.

Is there a connection between tattoos and lymphoma?

Any potential connection between tattoos and lymphoma has not been well studied. I could find only two published studies exploring the possibility, and neither found evidence of a compelling link.

The first study compared 737 people with the most common type of lymphoma (called non-Hodgkin's lymphoma) with otherwise similar people who did not have lymphoma. The researchers found no significant difference in the frequency of tattoos between the two groups.

A study published in May 2024 — the one that triggered the scary headlines above — was larger. It compared 1,398 people ages 20 to 60 who had lymphoma with 4,193 people who did not have lymphoma but who were otherwise similar. The study found that

• lymphoma was 21% more common among those with tattoos
• lymphoma risk varied depending on how much time had passed since getting the tattoo:
  • within two years, lymphoma risk was 81% higher
  • between three and 10 years, no definite increased lymphoma risk was detected
  • 11 or more years after getting a tattoo, lymphoma risk was 19%

There was no correlation between the size or number of tattoos and lymphoma risk.

What else should you know about the study?

Importantly, nearly all of the differences in rates of lymphoma between people with and without tattoos were not statistically significant. That means the reported link between lymphoma and tattoos is questionable — and quite possibly observed by chance. In fact, some of the other findings argue against a connection, such as the lack of a link between size or number of tattoos and lymphoma risk.

In addition, if tattoos significantly increase a person's risk of developing lymphoma, we might expect lymphoma rates in the US to be rising along with the popularity of tattoos. Yet that's not the case.

Finally, a study like this one (called an association study) cannot prove that a potential trigger of disease (in this case, tattoos) actually caused the disease (lymphoma). There may be other factors (called confounders) that are more common among people who have tattoos, and those factors might account for the higher lymphoma risk.

Do tattoos come with other health risks?

While complication rates from reputable and appropriately certified tattooists are low, there are health risks associated with tattoos:

• infection, including bacterial skin infections or viral hepatitis
• allergic reactions to the ink
• scarring
• rarely, skin cancer (melanoma and other types of skin cancer).

The bottom line

Despite headlines suggesting a link between tattoos and the risk of lymphoma, there's no convincing evidence it's true. We'll need significantly more research to say much more than that. In the meantime, there are more important health concerns to worry about and much better ways for all of us to reduce cancer risk.

About the Author

Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School. … See Full Bio View all posts by Robert H. Shmerling, MD

All of us have an internal clock that regulates our circadian rhythms, including when we sleep and when we are awake. And light is the single most important factor that helps establish when we should feel wakeful (generally during the day) and when we should feel sleepy (typically at night).

So, let me ask you a personal question: just how dark is your bedroom? To find out why that matters — and whether sleeping in an eye mask is worthwhile — read on.

How is light related to sleep?

Our circadian system evolved well before the advent of artificial light. As anyone who has been to Times Square can confirm, just a few watts of power can trick the brain into believing that it is daytime at any time of night. So, what’s keeping your bedroom alight?

• A tablet used in bed at night to watch a movie is more than 100 times brighter than being outside when there is a full moon.
• Working on or watching a computer screen at night is about 10 times brighter than standing in a well-lit parking lot.

Light exposure at night affects the natural processes that help prepare the body for sleep. Specifically, your pineal gland produces melatonin in response to darkness. This hormone is integral for the circadian regulation of sleep.

What happens when we are exposed to light at night?

Being exposed to light at night suppresses melatonin production, changing our sleep patterns. Compared to sleeping without a night light, adults who slept next to a night light had shallower sleep and more frequent arousals. Even outdoor artificial light at night, such as street lamps, has been linked with getting less sleep.

But the impact of light at night is not limited to just sleep. It’s also associated with increased risk of developing depressive symptoms, obesity, diabetes, and high blood pressure. Light exposure misaligned with our circadian rhythms — that is, dark during the day and light at night — is one reason scientists believe that shift work puts people at higher risk for serious health problems.

Could sleeping with an eye mask help?

Researchers from Cardiff University in the United Kingdom conducted a series of experiments to see if wearing an eye mask while sleeping at night could improve certain measures of learning and alertness.

Roughly 90 healthy young adults, 18 to 35 years of age, alternated between sleeping while wearing an eye mask or being exposed to light at night. They recorded their sleep patterns in a sleep diary.

In the first part of the study, participants wore an intact eye mask for a week. Then during the next week, they wore an eye mask with a hole exposing each eye so that the mask didn't block the light.

After sleeping with no light exposure (wearing the intact eye mask) and with minimal light exposure (the eye mask with the holes), participants completed three cognitive tasks on days six and seven of each week:

• First was a paired-associate learning task. This helps show how effectively a person can learn new associations. Here the task was learning related word pairs. Participants performed better after wearing an intact eye mask during sleep in the days leading up to the test than after being exposed to light at night.
• Second, the researchers administered a psychomotor vigilance test, which assesses alertness. Blocking light at night also improved reaction times on this task.
• Finally, a motor skill learning test was given, which involved tapping a five-digit sequence in the correct order. For this task, there was no difference in performance whether participants had worn an intact eye mask or been exposed to light at night.

What else did the researchers learn?

No research study is ever perfect, so it is important to take the conclusions above with a grain of salt.

According to sleep diary data, there was no difference in the amount of sleep, nor in their perceptions of sleep quality, regardless of whether people wore an eye mask or not.

Further, in a second experiment with about 30 participants, the researchers tracked sleep objectively using a monitoring device called the Dreem headband. They found no changes to the structure of sleep — for example, how much time participants spent in REM sleep — when wearing an eye mask.

Should I rush out to buy an eye mask before an important meeting or exam?

If you decide to try using an eye mask, you probably don’t need to pay extra for overnight shipping. Instead, follow a chronobiologist’s rule of thumb: “bright days, dark nights.”

• During the daytime, get as much natural daylight as you possibly can: go out to pick up your morning bagel from a local bakery, take a short walk during your afternoon lull at work.
• In the evening, reduce your exposure to electronic devices such as your cell phone, and use the night-dimming modes on these devices. Make sure that you turn off all unnecessary lights. Finally, try to make your bedroom as dark as possible when you go to bed. This could mean turning the alarm clock next to your bed away from you or covering up the light on a humidifier.

Of course, you might decide a well-fitted, comfortable eye mask is a useful addition to your light hygiene toolkit. Most cost $10 to $20, so you may find yourself snoozing better and improving cognitive performance for the price of a few cups of coffee.

About the Author

Eric Zhou, PhD, Contributor

Eric Zhou, PhD, is an assistant professor at Harvard Medical School. His research focuses on how we can better understand and treat sleep disorders in both pediatric and adult populations, including those with chronic illnesses. Dr. … See Full Bio View all posts by Eric Zhou, PhD

When you live in a coastal area, preparing early for potential hurricanes is a must. Storms can develop quickly, leaving little time to figure out where you’ll be safe or which items to pack if you have to evacuate. And health care necessities, such as medications or medical equipment, are often overlooked in the scramble.

“People might bring their diabetes medication but forget their blood sugar monitor, or bring their hearing aids but forget extra batteries for them,” says Dr. Scott Goldberg, medical director of emergency preparedness at Brigham and Women’s Hospital and a longtime member of a FEMA task force that responds to hurricane-damaged areas.

Here’s some insight on what to expect this hurricane season, and how to prioritize health care in your hurricane kit.

What will the 2024 hurricane season look like?

This year’s hurricane predictions underscore the urgency to start preparations now.

Forecasters with the National Oceanic and Atmospheric Administration’s National Weather Service expect above-normal activity for the 2024 hurricane season (which lasts until November 30).

Meteorologists anticipate 17 to 25 storms with winds of 39 mph or higher, including eight to 13 hurricanes — four to seven of which could be major hurricanes with 111 mph winds or higher.

What kinds of plans should you make?

Preparing for the possibility of big storms is a major undertaking. Long before ferocious winds and torrential rains arrive, you must gather hurricane supplies, figure out how to secure your home, and determine where to go if you need to evacuate (especially if you live in a flood zone). Contact the emergency management department at your city or county for shelter information.

If you’ll need help evacuating due to a medical condition, or if you’ll need medical assistance at a shelter, find out if your county or city has a special needs registry like this one in Florida. Signing up will enable first responders to notify you about storms and transport you to a special shelter that has medical staff, hospital cots, and possibly oxygen tanks.

What should you pack?

While a shelter provides a safe place to ride out a storm, including bathrooms, water, and basic meals, it’s up to you to bring everything else. It’s essential to pack medical equipment and sufficient medications and health supplies.

“It’s natural to just grab the prescription medications in your medicine cabinet, but what if it’s only a two-day supply? It might be a while before you can get a refill. We recommend at least a 14-day or 30-day supply of every prescription,” Dr. Goldberg says. “Talk to your doctor about the possibility of getting an extra refill to keep on standby for your go bag.”

Other health-related items you’ll want to pack include:

• medical supplies you use regularly, such as a blood pressure monitor, heart monitor, CPAP machine, wheelchair, or walker
• over-the-counter medicines you use regularly, such as heartburn medicine or pain relievers
• foods for specific dietary needs, such as gluten-free food if you have celiac disease (if you have infants or children, you’ll need to bring foods they can eat)
• healthy, nonperishable snacks such as nuts, nut butters, trail mix, dried fruit, granola bars, protein bars, and whole-grain bread, crackers, or cereals
• hygiene products such as soap, hand sanitizer, toothbrushes and toothpaste, shampoo, deodorant, infant or adult diapers, lip balm, moist towelettes, and toilet paper — because shelters often run out of it.

Remember the basics

In some ways, you can think of shelter living like camping. You’ll need lots of basic supplies to get through it, including:

• a sleeping bag or blanket and pillow for each person in your family
• clean towels and washcloths
• a few extra changes of clothes per person
• a first-aid kit
• flashlights and extra batteries
• chargers for your electronic gadgets
• rechargeable battery packs.

Bring important paperwork

In addition to supplies, bring important documents such as:

• a list of your medications, vitamins, and supplements (include the name, dose, and frequency of each one)
• a list of the names, addresses, and phone numbers of your primary care provider and any specialists who treat you
• a list of your emergency contacts and their phone numbers
• your pharmacy’s phone number and address
• copies of your birth certificate and driver’s license
• copies of home, car, or life insurance policies
• copies of your health insurance cards
• a copy of your advance directive — which includes your living will and health care proxy form.

“Store these documents on a flash drive. Also make photocopies of them, which are easiest for doctors to consult in an emergency setting. Place them in a plastic zip-top bag to keep them dry,” Dr. Goldberg advises.

Prepare right now

Start today. Gather as many go-bag supplies as you can, including the bags. A small suitcase, backpack, or duffel bag for each person in your family will work well.

And try not to put off these important preparations. “Hurricanes are major stressors. You might be worried, sleep deprived, fatigued, and emotional,” Dr. Goldberg says. “All of that will make it hard to think clearly. You’ll do yourself and your family a favor by having discussions now and getting started on your hurricane plan.”

About the Author

Heidi Godman, Executive Editor, Harvard Health Letter

Heidi Godman is the executive editor of the Harvard Health Letter. Before coming to the Health Letter, she was an award-winning television news anchor and medical reporter for 25 years. Heidi was named a journalism fellow … See Full Bio View all posts by Heidi Godman

About the Reviewer

Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing

Dr. Howard LeWine is a practicing internist at Brigham and Women’s Hospital in Boston, Chief Medical Editor at Harvard Health Publishing, and editor in chief of Harvard Men’s Health Watch. See Full Bio View all posts by Howard E. LeWine, MD

Cancer treatment can involve difficult tradeoffs, and that's also true of the testosterone-blocking drugs used in treating prostate cancer. These drugs work in two different ways. Androgen deprivation therapies (ADT) shut down the body's production of testosterone, a hormone that fuels prostate cancer growth. A newer class of drugs called androgen-receptor signaling inhibitors (ARSIs) block testosterone by deflecting the hormone from its cell receptor.

ADT can slow or control prostate cancer, and mounting evidence shows that adding ARSIs also improves survival when the disease is in advanced stages. This treatment combination is called intensified ADT. Researchers are now testing intensified ADT for some men with early-stage prostate cancer as well.

However, all drugs that block testosterone have challenging side effects, including metabolic changes that can compromise cardiovascular health. In June, British researchers reported that cardiovascular risks worsen when ADT and ARSIs are given together. The authors concluded that men who get intensified ADT should be counseled about the risks, and monitored for signs of heart disease before and after the treatment begins.

Study goals and results

The findings were derived from a systematic review of 24 clinical trials that assessed ADT and ARSI treatment for prostate cancer. Published between 2012 and 2024, the trials enrolled a combined total of 22,166 men ages 63 to 77. Their diagnoses ranged across the prostate cancer spectrum, from nonmetastatic cancer with aggressive features to metastatic prostate cancer that no longer responded to ADT by itself.

The goal of the systematic review was to compare ADT and intensified ADT with respect to cardiac events, including hypertension, cardiac arrhythmias (abnormal heartbeats), blood clots, or — in the worst case — heart attack or stroke.

Results showed that adding an ARSI to ADT approximately doubles the risk of a cardiac event across all prostate cancer states. Risks for severe "grade 3" events that can require hospitalization ranged between 7.8% and 15.6%. Notably, giving two ARSIs — abiraterone acetate and enzalutamide — led to a roughly fourfold increase in cardiac risk. Mounting evidence shows that combining abiraterone acetate and enzalutamide worsens side effects without improving prostate cancer survival. The use of that combination is now broadly discouraged by expert groups around the world.

The authors emphasize that intensified therapy is riskier for men with pre-existing cardiac conditions than it is for healthier men. In an accompanying editorial, Dr. Katelyn Atkins, a radiation oncologist at Cedars-Sinai Medical Center in Los Angeles, noted that cardiovascular disease is the second leading cause of death among men with prostate cancer.

Candidates for traditional or intensified ADT, Dr. Atkins wrote, should be assessed for atherosclerosis, fatty plaques in coronary arteries that can accumulate asymptomatically. Fortunately, cardiac risk factors are treatable by lowering blood pressure, eating a heart-healthy diet, exercising, and in some cases using a cholesterol-lowering drug called a statin.

Experts comment

"More and more research shows that intensive therapy prolongs survival, and may in some men even evoke a cure," said Dr. David Crawford, head of urologic oncology at the University of Colorado Anschutz Medical Campus who was not involved in the study. "We have learned time and again from the treatment of many cancers that it is not one drug followed by another and another that results in the best outcomes. Rather, it is combining drugs more effectively to treat the cancer.

"Still, we need to tackle the challenges of prostate cancer treatment and focus on preventing cardiovascular events and other side effects of ADT. As clinicians and in clinical studies, we have seen that men who maintain their weight, exercise, expand muscle mass, and maintain normal lipids and blood pressure do much better than men who gain weight and have a lot of cardiovascular risk factors."

"This important study re-emphasizes the necessity to keep a patient’s cardiovascular history front and center when treatment choices are made, " said Dr. Marc Garnick, the Gorman Brothers Professor of Medicine at Harvard Medical School and Beth Israel Deaconess Medical Center, and editor-in-chief of the Harvard Medical School Guide to Prostate Diseases.

"Intensification of treatment — that is, adding several drugs earlier and earlier in prostate cancer management — is to be both encouraged and cautioned. The caution is for physicians to consider and discuss pre-existing risk factors and how to modify them when deciding upon treatment programs. The ARSI class of drugs have greatly improved outcomes. The goal is to maximize the best outcomes while minimizing the side effects."

About the Author

Charlie Schmidt, Editor, Harvard Medical School Annual Report on Prostate Diseases

Charlie Schmidt is an award-winning freelance science writer based in Portland, Maine. In addition to writing for Harvard Health Publishing, Charlie has written for Science magazine, the Journal of the National Cancer Institute, Environmental Health Perspectives, … See Full Bio View all posts by Charlie Schmidt

About the Reviewer

Marc B. Garnick, MD, Editor in Chief, Harvard Medical School Annual Report on Prostate Diseases; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Marc B. Garnick is an internationally renowned expert in medical oncology and urologic cancer. A clinical professor of medicine at Harvard Medical School, he also maintains an active clinical practice at Beth Israel Deaconess Medical … See Full Bio View all posts by Marc B. Garnick, MD

Animals renowned for their outstanding night vision include owls, cats, tarsiers (a tiny primate in Southeast Asia) — and even the dung beetle.

But humans? Not so much.

Over time, many people suffer from night blindness, also known as nyctalopia. This condition makes seeing in dim or dark settings difficult because your eyes cannot adjust to changes in brightness or detect light.

What are the dangers for those experiencing night blindness?

Night blindness is especially problematic and dangerous when driving. Your eyes cannot adjust between darkness and the headlights of oncoming vehicles, other cars may appear out of focus, and your depth perception becomes impaired, which makes it difficult to judge distances.

Night blindness also may affect your sight at home by making it hard for your vision to quickly adjust to a dark room after turning off the lights. “This can cause people to bump into furniture or trip and suffer an injury,” says Dr. Isabel Deakins, an optometrist with Harvard-affiliated Massachusetts Eye and Ear.

What happens in the eye to create night blindness?

The ability to see in low-light conditions involves two structures in the eye: the retina and the iris.

The retina, located in the back of the eye, contains two types of light-detecting cells called cones and rods. The cones handle color vision and fine details while the rods manage vision in dim light.

The iris is the colored part of your eye. It contains muscles that widen or narrow the opening of your pupil to adjust how much light can enter your eyes.

If your irises don’t properly react, the pupils can dilate and let in too much light, which causes light sensitivity and makes it hard to see in bright light. Or your pupils may remain too small and not allow in enough light, making it tough to see in low light.

What causes night blindness?

Night blindness is not a disease but a symptom of other conditions. “It’s like having a bruise on your body. Something else causes it,” says Dr. Deakins.

Several conditions can cause night blindness. For instance, medications, such as antidepressants, antihistamines, and antipsychotics, can affect pupil size and how much light enters the eye.

Eye conditions that can cause night blindness include:

• glaucoma, a disease that damages the eye’s optic nerves and blood vessels
• cataracts, cloudy areas in the lens that distort or block the passage of light through the lens
• dry eye syndrome.

However, one issue that raises the risk of night blindness that you can’t control is age. “Our eyes react more slowly to light changes as we age, and vision naturally declines over time,” says Dr. Deakins.  “The number of rods in our eyes diminish, pupils get smaller, and the muscles of the irises weaken.”

What helps if you have night blindness?

If you notice any signs of night blindness, avoid driving and get checked by an eye care specialist like an optometrist or ophthalmologist. An eye exam can determine if your eyeglass prescription needs to be updated.

“Often, a prescription change is enough to reduce glare when driving at night," says Dr. Deakins. “You may even need separate glasses with a stronger eye prescription that you wear only when driving at night.”

Adding an anti-reflective coating to your lens may help to cut down on the glare of the headlights of an oncoming car. However, skip the over-the-counter polarized driving glasses sold at many drug stores. "These may help cut down on glare, but they don't address the causes of night blindness," says Dr. Deakins.

An eye exam also will identify glaucoma or cataracts, which can be treated. Glaucoma treatments include eyedrops, laser treatment, or surgery. Cataracts are corrected with surgery to replace the clouded lens with an artificial one. Your eye care specialist can also help identify dry eye and recommend treatment.

Ask your primary care clinician or a pharmacist if any medications that you take may cause night blindness. If so, it may be possible to adjust the dose or switch to another drug.

Three more ways to make night driving safer

You also can take steps to make night driving safer. For example:

• Wash the lenses of your glasses regularly. And take them to an optician to buff out minor scratches.
• Keep both sides of your front and rear car windshields clean so that you can see as clearly as possible.
• Dim your dashboard lights, which cause glare, and use the night setting on your rearview mirror.

About the Author

Matthew Solan, Executive Editor, Harvard Men's Health Watch

Matthew Solan is the executive editor of Harvard Men’s Health Watch. He previously served as executive editor for UCLA Health’s Healthy Years and as a contributor to Duke Medicine’s Health News and Weill Cornell Medical College’s … See Full Bio View all posts by Matthew Solan

About the Reviewer

Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing

Dr. Howard LeWine is a practicing internist at Brigham and Women’s Hospital in Boston, Chief Medical Editor at Harvard Health Publishing, and editor in chief of Harvard Men’s Health Watch. See Full Bio View all posts by Howard E. LeWine, MD

If you’re struggling with depression, the most important question about taking an antidepressant is whether it will work. But another question on your mind may be whether it will fuel weight gain.

A new study provides some context by suggesting how much weight, on average, people taking one of eight commonly used antidepressants might expect to gain. This insight is valuable, since people with depression often stop taking antidepressants because they don’t like the effect on their weight, a Harvard expert says.

“It’s important to acknowledge that weight gain is a key reason that some people decide to stop antidepressants, even if they’re otherwise working well,” says Dr. Roy Perlis, associate chief of psychiatric research at Massachusetts General Hospital. “It’s also a reason people may be reluctant to start them in the first place, even if they’re quite depressed or anxious.”

What did the study look at?

Published July 2024 in Annals of Internal Medicine, the new study drew on data from more than 183,000 people between ages 20 and 80. Their average age was 48, and 65% were women. Most were overweight or obese at the study’s start.

The researchers analyzed participants’ electronic health records and body mass index. They gauged weight gain or loss at regular intervals — six, 12, and 24 months — after people began taking an antidepressant for the first time.

The study compared the weight-related effects of sertraline (Zoloft) to seven other antidepressant medications:

• escitalopram (Lexapro)
• paroxetine (Paxil)
• duloxetine (Cymbalta)
• citalopram (Celexa)
• fluoxetine (Prozac)
• venlafaxine (Effexor)
• bupropion (Wellbutrin).

What did the research find?

The antidepressants led to the following average weight gain:

• sertraline: Nearly 0.5 pounds at six months; 3.2 pounds at 24 months
• escitalopram: 1.4 pounds at six months; 3.6 pounds at 24 months
• paroxetine: 1.4 pounds at six months; 2.9 pounds at 24 months
• duloxetine: 1.2 pounds at six months; 1.7 pounds at 24 months.

Citalopram, fluoxetine, and venlafaxine didn’t confer lower or higher odds of weight gain than Zoloft, the study found. And only bupropion was associated with a small amount of weight loss — 0.25-pounds — at six months. But that trend reversed at 24 months, when bupropion led to an average weight gain of 1.2 pounds.

What does the study tell us?

“Weight gain is common among antidepressant users, even if the amounts gained on average are modest,” says Dr. Perlis, who was not involved in this new study. It underscores similar findings from other studies of antidepressants, including research he published with colleagues a decade ago.

“While differences in weight gain for specific antidepressants tend to be small, there are certainly some — like bupropion — that tend to cause less weight gain,” he notes.

It’s crucial to keep in mind that the study points out average weight gain. Many people taking antidepressants won’t gain any weight and others could gain more. “Still, having average values to work with — and seeing that these averages line up well with prior studies — at least lets us give people a sense of what they might expect,” he says.

“One caution is that some people lose weight as a result of depression, which can impact appetite,” he adds, “so some of what we’re seeing may be people regaining weight they’d lost as their depression or anxiety improves.”

What additional limitations did the study have?

Other limitations may have shaped the findings. The study was observational, meaning it cannot prove that antidepressants cause weight changes, only that they were linked with them. It wasn’t a randomized, controlled trial — considered the gold standard in research — and the participants taking antidepressants weren’t compared to a control group not taking the medications.

Additionally, only about one in three participants was still taking their initially prescribed medication six months after the study started. That makes it difficult to link any later weight changes with a specific medication.

“As with any study that’s not randomized, we don’t know if the differences between medicines could reflect other differences in who gets prescribed these medicines,” Dr. Perlis says. “But, for circumstances where a randomized trial is unrealistic, health records can be a helpful way of trying to study side effects and at least generate a partial answer to these important questions.”

What else should you consider?

Another thing to consider, if you’re taking an antidepressant, is what types of side effects you’re willing to tolerate in pursuit of its mood-smoothing benefits.

“The best way to manage side effects is to anticipate them — to have an open conversation with your doctor about the potential risks and how we’ll manage them if they occur,” Dr. Perlis says.

What can you discuss with your doctor?

If weight gain is a particular concern for you, you may also wish to consider nondrug treatments for depression. They include:

• Cognitive behavioral therapy (CBT), a type of psychotherapy that teaches people to become aware of their thought patterns and adjust them during stressful moments to reframe their thinking.
• Repetitive transcranial magnetic stimulation (rTMS), a brain stimulation therapy that is noninvasive. It uses an electromagnetic coil placed on the scalp to deliver magnetic pulses that stimulate nerve cells to brain regions involved in depression.

“We know that certain kinds of talk therapies, especially cognitive behavioral therapy, can be very effective for treating depression and anxiety disorders,” Dr. Perlis says. “Whether people choose talk therapy or antidepressant medications can depend on their preference. It’s important to have multiple options.”

About the Author

Maureen Salamon, Executive Editor, Harvard Women's Health Watch

Maureen Salamon is executive editor of Harvard Women’s Health Watch. She began her career as a newspaper reporter and later covered health and medicine for a wide variety of websites, magazines, and hospitals. Her work has … See Full Bio View all posts by Maureen Salamon

About the Reviewer

Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing

Dr. Howard LeWine is a practicing internist at Brigham and Women’s Hospital in Boston, Chief Medical Editor at Harvard Health Publishing, and editor in chief of Harvard Men’s Health Watch. See Full Bio View all posts by Howard E. LeWine, MD

Dementia usually develops in people ages 65 years and older. So-called young-onset dementia, occurring in those younger than age 65, is uncommon. Now, a new study published in December 2023 in JAMA Neurology has identified 15 factors linked to a higher risk of young-onset dementia.

Let’s see what they found, and — most importantly — what you can do to reduce your own risks.

Are early dementia and young-onset dementia the same?

No. Experts think of early dementia as the first stage in dementia. Mild cognitive impairment and mild dementia are forms of early dementia. So, someone age 50, 65, or 88 could have early dementia.

Young-onset dementia refers to the age at which dementia is diagnosed. A person has young-onset dementia if symptoms and diagnosis occur before age 65.

What has previous research shown?

A previous study of men in Sweden identified some risk factors for young-onset dementia, including high blood pressure, stroke, depression, alcohol use disorder, vitamin D deficiency, drug use disorder, and overall cognitive function.

What to know about the new study

In the new study, a research team in the Netherlands and the United Kingdom looked at data from the UK Biobank. The biobank follows about half a million individuals in the United Kingdom who were 37 to 73 years old when they first joined the project between 2006 and 2010. Most participants identified as white (89%), and the remaining 11% were described only as “other.” Slightly more than half of the participants (54%) were women.

The researchers excluded anyone age 65 or older and people who already had dementia at the start of the study, leaving 356,052 participants for the analyses. Over roughly a decade, 485 participants developed young-onset dementia. The researchers compared participants who did and did not develop young-onset dementia to identify possible risk factors.

What did the researchers learn about risks for young-onset dementia?

In reviewing the results, I think it is helpful to group the risk factors into several categories, and then to examine each of them. These risks may act on the brain directly or indirectly.

Eight factors that we know or strongly suspect cause dementia:

• Genes: Carrying two apolipoprotein E (APOE) ε4 alleles is a major genetic risk factor for Alzheimer’s disease. The risk is thought to be caused by the APOE ε4 protein not clearing amyloid efficiently from the brain. This allows amyloid to accumulate and cause plaques, which starts the cascade to cell death and Alzheimer’s disease.
• Being diagnosed with alcohol use disorder (AUD) has been associated with damage to several parts of the brain, including the frontal lobes, which leads to trouble with executive function and working memory. When combined with poor nutrition, AUD also harms small regions connected to the hippocampus that are critical for forming new memories.
• Being socially isolated is a major risk factor for dementia. Although the exact mechanism is unknown, it may be because our brains evolved, in large part, for social interactions. Individuals with fewer social contacts have fewer social interactions, and simply don’t use their brains enough to keep them healthy.
• Not getting enough vitamin D can lead to more viral infections. A number of studies suggest that certain viral infections increase your risk of dementia.
• Not hearing well increases your risk for dementia, as I discussed in a prior post. This is likely because of reduced brain stimulation and reduced social interactions. Using hearing aids lessens that risk.
• Previously having had a stroke is a risk factor because strokes damage the brain directly, which can lead to vascular dementia.
• Having heart disease is a major risk factor for strokes, which can then lead to vascular dementia.
• Having diabetes if you’re a man can lead to dementia in many different ways. Why only if you’re a man? The researchers suggest that it is because middle-aged men are more likely to have a diabetes-related ministrokes than middle-aged women, which can, again, lead to vascular dementia.

Two factors that reduce cognitive reserve

Cognitive reserve can be described as our capacity to think, improvise, and problem-solve even as our brains change with age. These two risk factors make it more likely that dementia symptoms will show up at a younger age.

• Having less formal education may affect your familiarity with the items on the pencil-and-paper cognitive tests that are used to diagnose dementia.
• Having lower socioeconomic status may be related to lower-quality education.

Is every factor identified in the study a clear risk?

No, and here’s why not: Sometimes research turns up apparent risk factors that might be due to reverse causation. It’s possible, for example, that symptoms of impending dementia appear to be risk factors because they become noticeable before obvious dementia is diagnosed.

• Lower handgrip strength is a sign of frailty, which is often associated with dementia.
• No alcohol use is a risk factor because people may stop drinking when they develop memory loss (also known as the “healthy drinker effect” in dementia).
• Depression is a risk factor because many people get sad when they have trouble remembering or when they are worried about having dementia.

Lastly, there are risk factors that could be either a contributing cause or a result of the impending dementia.

• High C-reactive protein is a sign of inflammation.
• Orthostatic hypotension is an abnormal drop in blood pressure when a person stands up after lying down or sitting. While this condition can lead to brain damage and dementia, it can also be a result of some types of dementia, such as Parkinson’s disease dementia and dementia with Lewy bodies.

What can you do to prevent young-onset dementia?

Taking these five steps can reduce your risk for developing dementia before age 65:

• Don’t drink alcohol in excess.
• Seek opportunities to socialize with others regularly.
• Make sure that you’re getting enough vitamin D. You can make your own vitamin D if your skin (without sunblock) is exposed to sunlight. But in northern climates you might need to take a supplement, especially in the winter. Because vitamin D can interact with other medications, ask your doctor about this option.
• Make sure you are hearing well and use hearing aids if you are not.
• Exercise regularly, eat a healthy diet, maintain a healthy body weight, and work with your doctor to reduce your risk of strokes, heart disease, and diabetes.

About the Author

Andrew E. Budson, MD, Contributor; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Andrew E. Budson is chief of cognitive & behavioral neurology at the Veterans Affairs Boston Healthcare System, lecturer in neurology at Harvard Medical School, and chair of the Science of Learning Innovation Group at the … See Full Bio View all posts by Andrew E. Budson, MD

They say that parenting is the greatest — and the most challenging — job that many of us will ever land. Life can be tough for kids too, especially when they go through emotionally trying times.

What can parents do to help their kids manage episodes of anger, sadness, or anxiety triggered by school, siblings, and daily living? Whether you are a parent to an elementary-age child, a tweener ages 8 to 12, or a teenager, practicing two skills can help both you and your child: validation and coping.

Practicing validation

Validation teaches your children that feeling and expressing their emotions is okay.

“When parents use validation, they are affirming to their child that it’s fine to feel emotions and they should not be suppressed,” says Dr. Chase Samsel with the Department of Psychiatry and Behavioral Sciences at Harvard-affiliated Boston Children’s Hospital. “It shows them you understand their feelings and point of view, and it establishes trust. This, in turn, can help a child feel supported and open to discussing solutions.”

Start with acknowledgement

Acknowledge their emotions with comments like, “It sounds like you are frustrated or angry,” or “I can see that you’ve had a tough day at school.”

But which emotion — or emotions — is your child feeling? “It can be difficult for parents to recognize the genuine emotion their child is battling,” says Dr. Samsel. “Many times, kids have an emotional reaction but can’t explain what’s going on, or don’t want to, or express various emotions at once.”

Other times, different emotions lie underneath the one being shown. This is especially common among teenagers where they display anger, but often the real emotion is fear, anxiety, or sadness. “In these incidences, just recognizing they are going through something difficult is enough,” says Dr. Samsel.

Practice validation often

A child may not respond to validation at first — they may not want to talk about their emotions or may ignore your interest. But consistent validation will eventually pay off.

“By repeating validation when emotional crises arise, the child soon will become more comfortable expressing their emotion,” says Dr. Samsel. “Once they recognize that their parents welcome this and will not be reprimanded, they will be open to sharing details.”

Building a coping skills toolbox

Coping skills are ways parents can teach their children to manage emotional problems when they arise.

Try a breathing exercise together

Breathing exercises are a popular strategy, as they are easy to learn and quick to use. Dr. Samsel recommends any of the following: three-part breathing, ujjayi breathing, and belly breathing.

Other coping skills include guided meditation, visualization, squeezing a ball for stress relief, taking a walk or playing outside, and reading together (ideal for preschool and elementary-age children).

“Sometimes just giving children alone time in their room or “taking space” works well,” says Dr. Samsel.

Tap into coping skills yourself

It’s also vital for parents to adopt these strategies when dealing with their own emotions, says Dr. Samsel. Not only will this help you feel calmer, but it’s a great way to model that coping skills help everyone — adults, too!

For example, try telling your kids when you feel upset or frustrated about something that happens during your day. Announce that you plan to take a walk to de-stress or do a breathing exercise. Later, share your strategies for problem-solving.

“Kids watch what their parents do and will often mimic their behavior,” says Dr. Samsel. “If they see you constructively working through your emotions, they will be more open to doing the same.”

Be flexible

Never insist on having older kids use a coping mechanism, even when situations call for it. That could feel like punishment and trigger an automatic resistance.

Instead, Dr. Samsel suggests parents expose their children to different types of coping skills and then let them decide which ones they want to try. “They may need to experiment to find techniques they can easily follow and that work for them,” says Dr. Samsel.

About the Author

Matthew Solan, Executive Editor, Harvard Men's Health Watch

Matthew Solan is the executive editor of Harvard Men’s Health Watch. He previously served as executive editor for UCLA Health’s Healthy Years and as a contributor to Duke Medicine’s Health News and Weill Cornell Medical College’s … See Full Bio View all posts by Matthew Solan

About the Reviewer

Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing

Dr. Howard LeWine is a practicing internist at Brigham and Women’s Hospital in Boston, Chief Medical Editor at Harvard Health Publishing, and editor in chief of Harvard Men’s Health Watch. See Full Bio View all posts by Howard E. LeWine, MD

Sustainable living treads lightly on natural resources and follows a rethink, reuse, repurpose mantra to minimize waste.

Big and small wallet-friendly tips can help you save money and befriend our planet this summer, says Dr. Wynne Armand, a primary care physician at Harvard-affiliated Massachusetts General Hospital, and associate director of the Mass General Center for the Environment and Health. Here are five great tips to get you started.

1. Embrace the 5 Rs

Refuse, reduce, reuse, repurpose, and only then recycle is a well-laid out sustainability strategy promoted online by the Cincinnati Recycling and Reuse Hub. Do you really want or need a shiny new object? Where can you share tasks or tools? What could you swap, give away, or buy used? How could you slim down your recycling stream?

Give yourself permission to start here: Nobody is perfect. We all have preferences and sustainability blind spots, fumbles, and “sorry, just no” feelings. Start where you are and add on when you can.

2. Cut down on cooling energy

Summer heat can endanger your health, and paring back on energy use isn’t always possible or wise. Still, it may be possible to:

• Stay cooler naturally. Pull down shades during daytime hours to block out hot sun. Open windows at night if the temperature cools down, and to capture cross breezes if possible. Dress in loose cotton clothes and wear a shading hat when outdoors. Remember that sun bounces off lighter colors and is soaked up by black or darker colors. Make your own shade by carrying an umbrella on sunny — not just rainy — days. “Prepare meals that don’t require cooking or baking, since that saves resources and keeps your home cooler,” advises Dr. Armand.
• Seek shade and cool spots. If you don’t have air conditioning or you worry about the bills, green, leafy spaces like parks can help cool you down. Cities and towns often open cooling centers, splash pads, and public pools. Public buildings like libraries and malls are available during daytime hours for anyone trying to beat the heat.
• Turn up the temperature. On air conditioning, that is. If you’re fortunate enough to have air conditioning at home, follow natural cues. When you’re shivering, sweater-seeking, or tucked up under blankets, push the temperature up to save energy and money.

3. Save resources

A sharp eye for energy savings may help pare down bills, too.

• Electrify. Shrink your carbon footprint and help cut air pollution by using electric grills, mowers, and other landscaping tools. When tools or appliances need to be replaced, consider electric options.
• Conserve energy. Turn off electrical equipment that is not in use in the office and at home, such as lights, TVs, computers, copiers, and printers. 
• Go low when demand is high. “During peak electricity demand, ensuring stability of the grid is essential to public health,” says Dr. Armand. “Avoid using appliances like dishwashers, washers, or dryers during periods of high demand. Instead, do these chores — and charge your electric car, if you have one — late at night.” Some energy-hogging appliances have timers to help with this.
• Sign up for Shave the Peak alerts. Know when to curb your electricity use to avoid times when your local electric grid is relying on nonrenewable, expensive, polluting fossil fuels.

4. Stay heat-aware and hydrated

Saving resources is a worthy goal, but not at the expense of staying safe and healthy when summer temperatures spike.

• Make plans to stay cool. When summer swelters, having an affordable, personal plan to cool down — especially during heat waves — can be lifesaving.
• Watch out for signs of dehydration. Drinking plenty of water and eating water-rich foods like lettuce, cucumbers, melon, and citrus fruits can help you stay well hydrated. Water-filling stations for reusable bottles cut down on single-use plastic bottles and help save money at the grocery store.
• Know how to treat heat rash and more serious heat-related illnesses. The small, itchy red or darkened bumps of heat rash (prickly heat) occur when sweat ducts become blocked or inflamed. This makes it harder for children and adults to cool their bodies down. Generally, too much heat can harm our bodies, particularly if we work outdoors, take certain medicines, or have certain illnesses.

5. Kickstart sharing circles

Sharing circles can help you expand a wardrobe, tool shed, or taste in foods — all while building community.

• Start local, then consider expanding. Brainstorm with a few friends on what you all might like to share or swap. Think seasonal: gardening tools, outside décor, summer sports (because not everyone needs to own a paddleboard). Local clubs, block associations, or public spaces like libraries and schools may be willing to host community swaps and shares. Some communities have swap sheds and some libraries loan gadgets and even appliances like a portable induction cooktop burner, tech and home-improvement tools, games, and much more.
• Summer supper club. Perfect for those overloaded with summer harvests from window boxes, community gardens, or a CSA share. Build a theme around what’s fresh, local, and low-cost. Plant-forward menus are good for health and for the planet. Cultural inspiration always helps. And having one person cook — or stressing no-cook recipes — saves resources.
• Cut your clothing allowance. Tired of your wardrobe? Gather friends for a summer clothes and accessories swap. Be sure to agree on rules: gently-used, carefully washed, no stains, and so on.
• Hot spots. “Gathering at a friend’s or neighbor’s home for fun games and festivities on hot days is a great way to build community while saving on energy costs for cooling. And rotate for that next hot day!” says Dr. Armand. 

About the Author

Francesca Coltrera, Editor, Harvard Health Blog

Francesca Coltrera is editor of the Harvard Health Blog, and associate editor of multimedia content for Harvard Health Publishing. She is an award-winning medical writer and co-author of Living Through Breast Cancer and The Breast Cancer … See Full Bio View all posts by Francesca Coltrera

About the Reviewer

Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing

Dr. Howard LeWine is a practicing internist at Brigham and Women’s Hospital in Boston, Chief Medical Editor at Harvard Health Publishing, and editor in chief of Harvard Men’s Health Watch. See Full Bio View all posts by Howard E. LeWine, MD