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

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

Mosquitoes are not just a buzzing summertime nuisance; they can carry serious diseases like West Nile virus, malaria, and Zika. In recent months, the US has seen an unusual spike in the mosquito-borne illness dengue fever, also known as breakbone fever.

What is dengue, and where is it occurring in the US? How does it spread? And what steps can you take to protect against this and other mosquito-borne illnesses?

What is dengue and what are its symptoms?

Dengue is a viral disease caused by any of four closely-related viruses: dengue virus 1, 2, 3, and 4. Not everyone infected with dengue will become sick: only about one in four will experience symptoms that range from minimal discomfort to serious problems. A blood test is used to confirm the diagnosis.

When symptoms do occur, they tend to feel like the flu. The onset of feeling unwell usually begins within two to three days of being bitten by an infected mosquito but can take up to six to nine days, says Dr. Edward Ryan, director of global infectious diseases at Harvard-affiliated Massachusetts General Hospital.

Seek medical advice if you have recently traveled to an area with a risk of dengue and have a fever (101° F or higher) combined with any of these symptoms:

• aches and pains (often headache or pain behind the eye or in muscles, joints, or bones)
• nausea and vomiting
• a rash (faint red blotches).

About one in 20 people who gets sick will develop severe dengue, which requires emergency care. Those at an increased risk for severe dengue include infants a year or younger, pregnant women, adults ages 65 years or older, and those with previous dengue infections.

Symptoms of severe dengue require immediate medical care. They include:

• feeling very weak and lightheaded from low blood pressure
• bleeding from the nose or gums
• stomach swelling
• vomiting
• extreme fatigue.

How is dengue treated?

Dengue is cause by a virus, and no specific medications are available to combat it. Milder dengue symptoms typically last two to seven days, according to the Centers for Disease Control and Prevention (CDC). The symptoms are managed supportively: plenty of fluids, over-the-counter pain medications, and rest.

Severe dengue usually requires treatment in a hospital with intravenous (IV) fluids. Patients are monitored until their fever breaks and symptoms begin to wane. This usually happens in about three to five days. Recovery at home can last many more days before a person’s strength returns.

“While there are reports of people dying from severe dengue fever, deaths from dengue cases in the US are rare,” says Dr. Ryan.

How does dengue spread?

The viruses that cause dengue do not directly spread from person to person. Aedes species mosquitoes can become infected with the dengue virus when they bite a person who has the virus. Infected mosquitoes then spread the virus to other people.

US visitors to high-risk countries may unknowingly bring the virus home with them, giving dengue infection a chance to spread further. For example, an infected person will have dengue virus circulating in their bloodstream for up to one week after being bitten. Let’s say the person returns to the US sooner than seven days, where they get bitten by a mosquito. That mosquito in the US now carries the virus and could bite someone else, thereby spreading the infection.

Where is dengue occurring in the US?

Most dengue transmission in the United States happens in areas where this illness is already common, such as Puerto Rico, American Samoa, and the US Virgin Islands.

At this writing, the CDC has reported nearly 3,000 dengue cases in the United States and US territories. States with the highest reported instances include Florida, New York, Massachusetts, and California. (Puerto Rico, which declared a public health emergency in March, had reported almost 1,500 cases by late June 2024.) While US cases are higher than in previous years, they are still low compared to the global incidence of dengue, which hit a record 9.7 million cases in North, Central, and South America during the first six months of 2024.

It’s not clear what has caused the sudden rise in dengue cases. Dr. Ryan says it could be due to several factors, such as higher seasonal travel, more people living closer together in urban settings, and the fact that there are more mosquitoes are carrying dengue.

Is there a dengue vaccine?

Currently, there is no widely available dengue vaccine for US travelers. One FDA-approved vaccine, Dengvaxia, protects children ages 9 to 16 from all four types of dengue. It is used only for children who have had a previous infection and who live in areas where dengue is common. However, the vaccine will be discontinued in September 2025, with the final doses expiring in September 2026.

What steps can you take to prevent dengue?

The best way to prevent dengue when visiting high-risk areas and after returning home is to protect yourself from mosquito bites. Here are some tips from the CDC:

• Use EPA-registered insect repellents with one of the following active ingredients: DEET; picaridin (known as KBR 3023 and icaridin outside the United States); IR3535; oil of lemon eucalyptus (OLE) or 2-undecanone (plant-derived ingredients); or para-menthane-diol (PMD).
• Wear loose-fitting, long-sleeved shirts and pants.
• Wear clothing and gear treated with permethrin (an insecticide that kills or repels mosquitoes).
• Place screens on windows and doors.
• When traveling, stay in places with air conditioning and screens. Use a bed net if air-conditioned or screened rooms are unavailable or if sleeping outdoors.
• To prevent mosquitoes from laying eggs in or near water around your home, empty and scrub, turn over, cover, or throw out outdoor items that hold water. This includes tires, buckets, toys, kid pools, birdbaths, flower pot saucers, or trash containers.

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

Before going any further, here’s the main thing parents should know about swimming lessons: all children should have them.

Every year, over 4,500 people die from drowning in the United States — and, in fact, drowning is the leading cause of death for children ages 1 to 4. Swimming lessons can’t prevent all of those deaths, but they can prevent a lot of them. A child doesn’t need to be able to swim butterfly or do flip turns, but the ability to get back to the surface, float, tread water, and swim to where they can stand or grab onto something can save a life.

10 things parents should know about swimming lessons

As you think about swimming lessons, it’s important to know:

1. Children don’t really have the cognitive skills to learn to swim until they are around 4 years old. They need to be able to listen, follow directions, and retain what they’ve learned, and that’s usually around 4 years old, with some kids being ready a little earlier.

2. That said, swim lessons between 1 and 4 years old can be useful. Not only are some kids simply ready earlier, younger children can learn some skills that can be useful if they fall into the water, like getting back to the side of a pool.

3. The pool or beach where children learn must be safe. This sounds obvious, but safety isn’t something you can assume; you need to check it out for yourself. The area should be clean and well maintained. There should be lifeguards that aren’t involved in teaching (since teachers can’t be looking at everyone at all times). There should be something that marks off areas of deeper water, and something to prevent children from getting into those deeper areas. There should be lifesaving and first aid equipment handy, and posted safety rules.

4. The teachers should be trained. Again, this sounds obvious — but it’s not always the case. Parents should ask about how teachers are trained and evaluated, and whether it’s under the guidelines of an agency such as the Red Cross or the YMCA.

5. The ratio of kids to teachers should be appropriate. Preferably, it should be as low as possible, especially for young children and new swimmers. In those cases, the teacher should be able to have all children within arm’s reach and be able to watch the whole group. As children gain skills the group can get a bit bigger, but there should never be more than the teacher can safely supervise.

6. There should be a curriculum and a progression — and children should be placed based on their ability. In general, swim lessons progress from getting used to the water all the way to becoming proficient at different strokes. There should be a clear way that children are assessed, and a clear plan for moving them ahead in their skills.

7. Parents should be able to watch for at least some portion. You should be able to see for yourself what is going on in the class. It’s not always useful or helpful for parents to be right there the whole time, as it can be distracting for children, but you should be able to watch at least the beginning and end of a lesson. Many pools have an observation window or deck.

8. Flotation devices should be used thoughtfully. There is a lot of debate about the use of “bubbles” or other flotation devices to help children learn to swim. They can be very helpful with keeping children safe at the beginning, and helping them learn proper positioning and stroke mechanics instead of swimming frantically to stay afloat, but if they are used, the lessons should be designed to gradually decrease any reliance on them.

9. Being scared of the water isn’t a reason not to take, or to quit, swimming lessons. It’s common and normal to be afraid of the water, and some children are more afraid than others. While you don’t want to force a child to do something they are terrified of doing, giving up isn’t a good idea either. Start more gradually, with lots of positive reinforcement. The swim teacher should be willing to help.

10. Just because a child can swim doesn’t mean he can’t drown. Children can get tired, hurt, trapped, snagged, or disoriented. Even strong swimmers can get into trouble. While swimming lessons help save lives, children should always, always be supervised around water, and should wear life jackets for boating and other water sports.

The Centers for Disease Control and Prevention website has helpful information on preventing drowning. The American Red Cross offers an online water safety course for caregivers and parents and water safety videos for children. Many public pools and organizations like Boys & Girls Clubs and the YMCA offer swimming classes for all ages.

About the Author

Claire McCarthy, MD, Senior Faculty Editor, Harvard Health Publishing

Claire McCarthy, MD, is a primary care pediatrician at Boston Children’s Hospital, and an assistant professor of pediatrics at Harvard Medical School. In addition to being a senior faculty editor for Harvard Health Publishing, Dr. McCarthy … See Full Bio View all posts by Claire McCarthy, MD

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

 

More than half of Americans live in states where recreational cannabis is legal. While alcohol remains the most-used drug in the US, daily cannabis use has actually outpaced daily drinking, according to a study following four decades of consumption trends. Changing drinking habits and new products likely play a role.

Are you rethinking drinking habits?

Growing interest in Dry January and the sober curious movement suggests many people — especially younger adults — are rethinking drinking habits. Sales of alcohol-free beverages have been on the rise. One popular new category in that mix is cannabis-infused beverages, says Dr. Staci Gruber, an associate professor of psychiatry at Harvard Medical School who directs the Marijuana Investigations for Neuroscientific Discovery (MIND) Program at McLean Hospital.

“People are interested in an experience that allows them to relax and enjoy themselves. Some are leaning into cannabis drinks as part of the ‘Cali sober’ trend,” says Dr. Gruber.

(Cali — or California — sober is an informal term used to describe people who abstain from alcohol, or just moderate their drinking, and avoid drugs other than cannabis. Some people include psychedelic drugs such psilocybin and LSD in their definition of Cali sober).

What are cannabis-infused drinks?

First, a brief primer on cannabis (marijuana). It comes from the Cannabis sativa plant, which contains more than 100 chemical compounds known as cannabinoids. These compounds interact with chemicals and receptors in the human brain.

• The most familiar cannabinoid is delta-9-tetrahydrocannabinol (THC), which produces intoxication or euphoria. For some people, it also helps ease pain and nausea.
• Another is cannabidiol (CBD), which is not intoxicating and has a number of potential medical uses, including anxiety-relieving properties.

Varieties of cannabis that contain low levels of THC (less than 0.3%) are classified as hemp, while those with more than 0.3% THC are considered cannabis. However, the type and amount of cannabinoids that different cannabis-based products claim to contain vary widely — and the labels aren’t necessarily accurate, says Dr. Gruber.

Many cannabis-infused drinks list THC as an ingredient, and while there is no standard dose, 5 milligrams (mg) is typically used in research studies of the drug. Some “low-dose” beverages contain 2 to 4 mg of THC in an 8-ounce container. Other products can contain as much as 200 mg of THC. The drinks may also contain caffeine, alcohol, or other substances.

State laws vary on whether and where these drinks can be sold and on age restrictions.

How do cannabis drinks differ from edibles?

Edibles are foods containing cannabis, such as gummies, brownies, or cookies.

The cannabinoids found in beverages are specially formulated to dissolve in liquid. This means they are more easily and rapidly absorbed into the body’s soft tissues.

“Some people say they feel the effects of cannabis-infused drinks within 15 to 20 minutes, which is much faster than when people eat a cannabis gummie or brownie,” says Dr. Gruber. Those products take at least 30 to 90 minutes to take effect because they must be digested and then processed through your liver, she explains.

How do the effects of cannabis drinks compare with alcoholic drinks?

While everyone is different, people generally know how they’re going to react if they drink, say, a light beer or two gin and tonics, says Dr. Gruber. But people are less familiar with the effects of cannabis in general — and of cannabis beverages in particular. That’s compounded by the varied amounts, mixtures, and other ingredients different drinks may contain.

If you down one cannabis drink and don’t wait long enough to feel the effects and have one or two more, you can double or triple your THC dose very quickly. “You can go from an experience that’s reasonably pleasant to one that’s not,” says Dr. Gruber.

Some people feel fine after small and sometimes even large amounts of THC. Others find even small amounts intolerable. “They may feel uneasy or anxious and their heart rate and blood pressure may rise. Nausea and vomiting are also possible, and some people even become paranoid and agitated,” says Dr. Gruber.

Are older adults more likely to experience unpleasant effects?

Possibly. Older adults may be more vulnerable to these unpleasant effects, in part because drug metabolism slows with age. After recreational cannabis became legal to sell in California, cannabis-related emergency department visits increased in older adults. The same trend occurred in Canada, as documented in a recent study in JAMA Internal Medicine.

This isn’t to suggest that cannabis drinks are more risky than alcohol, which has many unhealthy effects. Still, there are generally more unknowns with cannabis drinks, says Dr. Gruber.

“If you are interested in trying it and it is legal for you to do so, be mindful about controlling the experience until you know how a particular product affects you,” she says.

About the Author

Julie Corliss, Executive Editor, Harvard Heart Letter

Julie Corliss is the executive editor of the Harvard Heart Letter. Before working at Harvard, she was a medical writer and editor at HealthNews, a consumer newsletter affiliated with The New England Journal of Medicine. She … See Full Bio View all posts by Julie Corliss

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

Do you ever read the notes written by your doctor or health practitioner during a medical visit? If not, you might want to check them out. Usually, these medical notes are full of helpful insights about your health and reminders of recommendations discussed. And there’s medicalese, of course: hard-to-pronounce illnesses, medications, and technical terms.

But you may be surprised to see incorrect information or unexpected language, tone, or even innuendo. Was your past medical history really that “unremarkable”? Did you actually “deny” drinking alcohol? Did the note describe you as “unreliable”?

Here’s how to decipher unfamiliar lingo, understand some surprising descriptions, and flag any errors you find.

What’s in a medical note?

A standard medical note has several sections. These include

• a description of current symptoms
• past medical problems
• a list of medications taken
• family medical history
• social habits such as smoking, drinking alcohol, or drug use
• details of the physical examination
• test results
• a discussion of the big picture, along with recommendations for further evaluation or treatment.

Notes tend to be more complete for a new patient or annual exam. Follow-up notes may not cover all of these points.

What’s potentially confusing about medical notes?

Most medical notes aren’t written using plain language because they aren’t intended primarily for a nonmedical audience. So it’s common to run across:

• Medical jargon: You had an upset stomach and a fever. Doctors may say “dyspepsia” (upset stomach) and “febrile” (fever).
• Complicated disease names: Ever heard of “multicentric reticulohistiocytosis” or “progressive multifocal leukoencephalopathy?” These are just two of thousands of examples.
• Use of common language in uncommon ways: For example, your medical history might be called “unremarkable” and test results called "within normal limits” rather than “normal.”
• Abbreviations: You might see “VSS” and “RRR,” meaning “vital signs stable” with a pulse that has a “regular rate and rhythm.”

If you’re having trouble deciphering a note or understanding your health issues, tests, and recommendations, check in with your doctor’s office for clarifications. The more you understand about your health and your options for care, the better.

What if a medical note is incorrect?

Minor errors in medical notes are not rare: maybe you had your tonsils removed 30 years ago, not 10 years ago. But there can be more important errors: stating that arthritis in your left knee is severe when it’s actually the right knee that’s severe could lead to having x-rays (or even surgery!) on the wrong side. And not properly recording a family history of cancer or heart disease could mean missing out on timely screening tests or preventive treatments.

In an era of ever-increasing time pressure, use of voice recognition software, electronic record templates, drop-down menus, and ability to copy and paste text, it’s easier than ever for health care providers to make (and perpetuate) errors in the medical record.

If you do see an important error that could affect your health, ask your provider to amend it.

What if the language in a medical note seems offensive?

Numerous studies have highlighted the problem of stigmatizing language in medical notes that can leave people feeling judged or offended. Negative attitudes can affect the quality of our health care and willingness to seek care, and can also widen health disparities. One study linked stigmatizing language to higher rates of medical errors. Of note, this study found higher rates of stigmatizing language and medical error among black patients.

Examples include:

• Depersonalization: A note might describe a patient as “a drug abusing addict” rather than a person struggling with drug addiction.
• Insulting or inappropriate descriptors: Notes might contain subjective descriptions that paint the patient in an unflattering light without providing context. For example, the note might say “the patient is unkempt and is drug-seeking” rather than “the patient is experiencing homelessness and has severe, chronic pain.” If a person’s recall of medical events from the past is hazy, they may be called “unreliable.”
• Dismissiveness: A medical note may suggest a symptom is not real or is exaggerated, rather than taking the complaint seriously.
• An untrusting tone: Language such as “she claims she never drinks” or “he denies alcohol use” may suggest mistrust by the physician.

Why might this happen, anyway?

How does such language make its way into medical notes? (To be clear, these possible explanations are not justifications.)

• Tradition and training: Medical trainees, like other learners, tend to follow the lead of their mentors. So if stigmatizing language is used by an instructor, trainees may do the same.
• Time pressure: With medical documentation (as in most everything else), mistakes are more common if you’re rushing.
• Bias: Like everyone else, doctors have biases, including ones they aren’t aware of. How we are taught to think about people — by family, by society — can spill over into every area of life, including work.
• Frustration: Doctors may feel frustrated by patients who don’t follow their recommendations. That frustration can be reflected in their medical notes. For example, a note may say, “As expected, the patient’s blood sugar is high; he is still not checking his blood sugar or following the diet recommended by his nutritionist.”

If the language in a note is confusing or bothersome, ask about it. The Open Notes movement and federal legislation have given most of us much better access to our medical records. This has worthy goals — greater transparency and better communication with people about their medical care — and unintended consequences.

Is changing language in notes that health practitioners once shared mainly with each other a positive consequence? Mostly. Yet some doctors worry that notes will become less specific, accurate, or useful since they may leave out information that might upset a patient.

The bottom line

I encourage you to read your health providers’ notes about your care. If there is a substantial error or something you find confusing or objectionable, ask about it. By the way, a signed medical note cannot usually be revised. However, your doctor can make clarifications or correct mistakes in an addendum at the end of the note.

As more and more patients read their medical notes, it’s likely that health providers will be more conscientious about the language they use. So, wide access to medical notes may improve not only people’s understanding of their health, but also the quality of notes over time.

It's worth remembering that the medical note is not the most important thing that happens during a visit to your doctor. A great note isn’t the same as great care, and vice versa. Still, your medical notes can be a valuable source of health information that differs from all others, including trusted health sites and social media: they’re written by your doctor and they’re all about you.

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