April 30, 2024 | jyspvq

Protect your skin during heat waves — here’s how

Illustration of a hot yellow sun with orange-yellow rays surrounding it and a few floating clouds

Global average temperatures have soared in 2024, surpassing records set just last year. Extreme heat poses numerous health risks, some of which are visible on our skin. Understanding how heat affects your skin can help you take measures to prevent or ease heat rash, eczema, rosacea, the discoloration of melasma, and many other skin conditions sparked or worsened by high temperatures.

How does heat affect your skin?

Heat waves can provoke or worsen several skin conditions.

  • Heat rash (miliaria) occurs due to obstruction of sweat ducts on the skin, which are responsible for helping the body maintain a normal temperature by releasing water to the surface of the skin. As these sweat glands get blocked with excessive sweat on an extremely hot day, they do not function properly and red itchy bumps develop.
  • Grover disease, a rash of small, red, itchy bumps on the chest and back, can also be triggered or worsened by excessive heat and sweating. Often this clears up within a few weeks or months. Less often symptoms may persist for years, with flares during the summer months.
  • Eczema is a chronic skin condition characterized by dry, itchy plaques that affects millions of people in the United States. Increased sweating during heat waves can lead to skin irritation and inflammation, aggravating eczema symptoms. Dehydration caused by fluid loss through sweating can make the skin more susceptible to eczema flare-ups.
  • Rosacea, which causes facial redness, visible blood vessels, and acne-like bumps, is also heat-sensitive. Heat causes blood vessels to dilate as the body attempts to cool itself, resulting in visible redness and flushing. High temperatures, especially combined with sun exposure, can cause flare ups.
  • Melasma. Hyperpigmentation disorders like melasma also worsen with heat. Melasma is characterized by irregular dark patches on the face and is often triggered by UV exposure from the sun. Heat can increase the activity of melanocytes, the cells that produce pigment, making these patches more pronounced. Additionally, the combined effects of heat and UV radiation accelerate collagen and elastin degradation, leading to premature aging and loss of skin elasticity.
  • Skin cancer risk rises with increased exposure to UV radiation. Heat waves — now beginning earlier, ending later, and lasting longer — contribute to UV exposure, particularly among people who work outdoors. And preliminary research suggests prolonged exposure to high temperatures may further boost skin cancer risk. This could be of particular concern for firefighters, who face extended exposure to extreme heat.

Heat waves, air pollution, and skin

During heat waves, levels of environmental pollutants like ozone and particulate matter can rise. And reactions between these pollutants, heat, and UV radiation spawn secondary pollutants such as peroxyacetyl nitrates (PANs). Pollutants like these can irritate the skin and contribute to inflammation through oxidative stress and DNA damage, so inflammatory conditions such as eczema and rosacea may worsen.

Can heat affect medications?

High temperatures compromise the effectiveness of certain medications. For instance, EpiPens, which are crucial for managing life-threatening allergic reactions, can lose their potency when exposed to high temperatures. Check the instructions on all of your medicines to see which ones should be stored in a cool, dry place or refrigerated. If you’re not sure which medicines might be affected by heat, talk to your pharmacist or doctor.

Retinoids in skin care products, antibiotics taken for acne, and immunomodulators for autoimmune diseases can make skin more susceptible to sun damage. This can lead to severe sunburns or rashes known as photodermatoses. If you experience this, contact your health care team for advice.

Protect your skin when temperatures climb

Keep skin cool

  • Wear light, breathable clothing. Choose natural fibers like cotton and linen to help regulate body temperature and prevent sweat-induced skin issues. Avoid synthetic fabrics, which can trap heat and moisture.
  • Take cool baths or showers. Use cool or tepid water to bathe. Avoid hot showers, which can strip the skin of natural oils, leading to dryness and irritation.
  • Find cool spaces. If your home is not air-conditioned, seek out cooler places and ways to cool off during heat waves.

Keep skin hydrated

  • Drink ample water and eat water-rich foods. Foods like watermelon and cucumbers can provide additional hydration.
  • Moisturize your skin. Apply light, non-comedogenic moisturizers immediately after bathing. Look for ingredients such as hyaluronic acid and glycerin, which are beneficial for enhancing skin hydration.

Limit exposure to sun and pollution

  • Use protective clothing. Wear wide-brimmed hats, UV-blocking sunglasses, and long-sleeved shirts to shield the skin from harmful radiation.
  • Wear sunscreen. Apply broad-spectrum mineral sunscreens containing zinc oxide, titanium dioxide, or iron oxide to protect against UV radiation and pollutants.
  • Use topical antioxidants. Use products like vitamin C in your morning skin care routine to mitigate oxidative stress.
  • Wash up. Cleansing face and body at the end of the day may help you limit skin exposure to pollutants while also rinsing off any sunscreen residue.

About the Authors

photo of Kathyana P. Santiago Mangual

Kathyana P. Santiago Mangual, Contributor

Kathyana P. Santiago Mangual is a clinical research fellow in dermatology at Massachusetts General Hospital and Harvard Medical School. She is also a medical student at the University of California, Los Angeles, and will be graduating … See Full Bio View all posts by Kathyana P. Santiago Mangual photo of Arianne Shadi Kourosh, MD, MPH

Arianne Shadi Kourosh, MD, MPH, Contributor

Arianne Shadi Kourosh, MD, MPH, is a board certified dermatologist and associate professor of dermatology at Harvard Medical School. She is a graduate of the Harvard T.H. Chan School of Public Health and the University of … See Full Bio View all posts by Arianne Shadi Kourosh, MD, MPH

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April 27, 2024 | jyspvq

The popularity of e-bikes and e-scooters is soaring, but are they safe?

Woman in jeans, blue blazer, and helmet riding electric scooter on pathway with flowers and trees in background

Ever ridden an e-scooter or e-bike? The convenience, affordability, and flat-out fun of these “micromobility” modes of transportation are undeniable. But did it also seem a bit dangerous?

In fact, the rate of accidents involving e-bikes and e-scooters is climbing. Maybe that shouldn’t be surprising given their dramatic jump in popularity. And then there’s the way riders often use them: at high speed, near cars and pedestrians, and on roads and sidewalks that weren’t designed for them.

Disruptive innovations, such as e-bikes and e-scooters, inevitably come with downsides. So, how can we minimize risks for accidents?

E-bikes, e-scooters, and injuries

Between 2018 and 2022, sales of e-bikes rose from around 250,000 per year to more than a million. E-bike and e-scooter rentals have also increased dramatically. As their popularity grows, emergency rooms are seeing many more people injured while riding e-bikes and e-scooters.

A 2024 study in JAMA Network Open highlights this. Researchers drew data from the National Electronic Injury Surveillance System, which is run by the US Consumer Product Safety Commission. They analyzed ER care between 2017 and 2022 for people injured while riding an e-bike or e-scooter, compared with people injured while riding conventional bikes and scooters.

What did the study find?

During the six-year study period, roughly three million people riding e-bikes, e-scooters, or their conventional counterparts sought care in the ER, including about 45,500 e-bike riders and 190,000 e-scooter riders, and about 2.5 million conventional bike riders and 305,000 conventional scooter riders.

Certain themes emerged around e-micromobility:

ER care spiked upward

  • E-bike injuries more than doubled every year, going from 751 in 2017 to 23,493 in 2022.
  • E-scooter injuries increased by more than 45% every year, going from 8,566 in 2017 to 56,847 in 2022.

More risky behavior

  • 43% of e-bike and e-scooter riders wore helmets versus 52% for conventional micromobility riders
  • 7% of e-bike riders and 9% of e-scooter riders were drinking before their accidents versus 4% of conventional bike riders and 3% of conventional scooter riders.

More accidents occurred in urban areas compared with rural settings:

  • 83% of e-bike and e-scooter accidents
  • 71% of conventional bike and scooter accidents.

All riders experienced similar types of injuries: scrapes, bruises, broken bones, and head and neck injuries were most common.

What are the limitations of this study?

This study only included people evaluated in an ER, so it excluded people with less severe injuries — and even those with significant injuries who didn’t go to an ER. Some may have sought no care at all, or gone to a primary care practice or walk-in clinic to avoid costly ER care or for other reasons.

Nor did the study count injuries suffered by pedestrians injured by e-bike or e-scooter riders. Property damage, such as damage to a car, wasn’t calculated.

And ultimately the study cannot compare the safety of e-bikes and e-scooters with conventional options. That’s because no data were collected on the number of miles traveled using a particular mode of transportation, or over how much time.

How can you avoid e-bike or e-scooter injuries?

Ten common-sense precautions can help you avoid injuries and ER visits:

  • Wear a helmet. If you’re renting an e-bike or e-scooter, you may need to bring your own since many rental systems do not provide helmets.
  • Practice. E-bikes are much heavier than conventional bicycles and may handle differently. And many adults have not ridden a scooter since elementary school! So if you aren’t familiar with riding an e-bike or e-scooter, practice in a safe location where there’s no traffic or pedestrians.
  • Follow road rules. Ride on available bike lanes and avoid sidewalks. On an e-bike, use arm signals to alert those nearby of your intentions to turn or change lanes. (On an e-scooter, it’s best to keep both hands on the handle bars at all times.).
  • Slow down. Some e-bikes approach speeds of 30 miles per hour. The faster you go, the less time you have to react to unexpected potholes or veering vehicles, and the more serious an injury is likely to be if you have an accident.
  • Lower risks. Don’t ride while under the influence of alcohol or drugs, or use your phone while moving.
  • Go it alone. Don’t add riders. Most e-bikes and e-scooters are built for one rider at a time.
  • Ride defensively. Watch out for potholes or opening car doors.
  • Reflect. Wear reflective clothing or attach a light if riding at night.
  • Call out. Announce your presence to others. For example, shout “on your left!” as you approach pedestrians or slower riders that you intend to pass.
  • Lobby. Reach out to local politicians to create bike lanes and other infrastructure to make micromobility safer.

The bottom line

Whether it’s part of your daily commute, an occasional quick zip from point A to point B, or just a ride for the fun of it, e-bikes and e-scooters are a great way to get around. Though they do come with some risk, you can do a lot to minimize the odds of wrapping up your travels with a trip to an ER.

About the Author

photo of Robert H. Shmerling, MD

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

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April 9, 2024 | jyspvq

Are you getting health care you don’t need?

illustration in shades of green and white showing stylized medical objects: thermometer, bandage, medication bottle, stethoscope, syringe, clipboard, blister pack of pills

Ever wonder if every medical test or treatment you've taken was truly necessary? Or are you inclined to get every bit of health care you can? Maybe you feel good about getting the most out of your health insurance. Perhaps a neighborhood imaging center is advertising discounted screening tests, your employer offers health screens as a perk, or you're intrigued by ads touting supplements for a seemingly endless number of conditions.

But keep in mind: just because you could get a particular test or treatment or take a supplement doesn't mean you should. One study suggests that as much as 20% of all health care in the US is unneeded. In short: when it comes to health care, more is not always better.

Isn't it better to be proactive about your health?

We're all taught that knowledge is power. So it might seem reasonable to want to know as much as possible about how your body is working. And isn't it better to take action before there's a problem rather than waiting for one to develop? What's the harm of erring on the side of more rather than less?

The truth is that knowledge is not always power: if the information is irrelevant to your specific situation, redundant, or inaccurate, the knowledge gained through unnecessary health care can be unhelpful or even harmful. Unnecessary tests, treatments, and supplements come with risks, even when they seem harmless. And, of course, unnecessary care is not free — even if you're not paying a cent out of pocket, it drives up costs across health systems.

Screening tests, wellness strategies, and treatments to reconsider

Recommended screening tests, treatments, and supplements can be essential to good health. But when risks of harm outweigh benefits — or if proof of any benefit is lacking — think twice. Save your time, money, and effort for health care that is focused on the most important health threats and backed by evidence.

Cancer screening: When to stop?

Screening tests for some cancers are routinely recommended and can be lifesaving. But there's a reason they come with a recommended stop age. For instance, guidelines recommend that a person at average risk of colorectal cancer with previously normal colonoscopies stop having them once they turn 75. Similar limits apply to Pap smears (age 65) and mammograms (age 75). Studies suggest that beyond those ages, there is little benefit to continuing these screens.

Watch out for wellness marketing

Dietary supplements are a multibillion-dollar industry. And a whopping 70% or more of US adults take at least one, such as vitamin D, fish oil, or a multivitamin. People often consider them as insurance in case vital elements are missing from their diet, or they believe supplements can prevent dementia, heart disease, or another condition.

Yet little evidence supports a benefit of routine supplement use for everyone. While recent studies suggest a daily multivitamin might slow cognitive decline in older adults, there's no medical consensus that everyone should be taking a multivitamin. Fish oil (omega-3) supplements haven't proven to be as healthful as simply eating servings of fatty fish and other seafood low in toxic chemicals like mercury and PCBs. And the benefits of routinely taking vitamin D supplements remain unproven as well.

It's worth emphasizing that dietary supplements clearly provide significant benefit for some people, and may be recommended by your doctor accordingly. For example, if you have a vitamin or mineral deficiency or a condition like age-related macular degeneration, good evidence supports taking specific supplements.

Reconsider daily aspirin

Who should be taking low-dose aspirin regularly? Recommendations have changed in recent years, so this is worth revisiting with your health care team.

  • Older recommendations favored daily low-dose aspirin to help prevent cardiovascular disease, including first instances of heart attack and stroke.
  • New recommendations favor low-dose aspirin for people who've already experienced a heart attack, stroke, or other cardiovascular disease. Adults ages 40 to 59 who are at a high risk for these conditions and low risk for bleeding also may consider it.

Yet according to a recent study, nearly one-third of adults 60 and older without past cardiovascular disease take aspirin, despite evidence that it provides little benefit for those at average or low risk. Aspirin can cause stomach bleeding and raise risk for a certain type of stroke.

Weigh in on prostate cancer screening

Men hear about prostate cancer often. It's common, and the second leading cause of cancer deaths among men. But PSA blood tests and rectal exams to identify evidence of cancer in the prostate are no longer routinely recommended for men ages 55 to 69 by the United States Preventative Services Task Force.

The reason? Studies suggest that performing these tests does not reliably reduce suffering or prolong life. Nor do possible benefits offset downsides like false positives (test results that are abnormal despite the absence of cancer). That can lead to additional testing, some of which is invasive.

Current guidelines suggest making a shared decision with your doctor about whether to have PSA testing after reviewing the pros and cons. For men over age 70, no screening is recommended. Despite this, millions of men have PSA tests and rectal examinations routinely.

Not everyone needs heart tests

There are now more ways than ever to evaluate the health of your heart. But none are routinely recommended if you're at low risk and have no signs or symptoms of cardiovascular disease. That's right: in the absence of symptoms or a high risk of cardiovascular disease, it's generally safe to skip EKGs, stress tests, and other cardiac tests.

Yet many people have these tests as part of their routine care. Why is this a problem? Having these tests without a compelling reason comes with risks, especially false positive results that can lead to invasive testing and unneeded treatment.

Four more reasons to avoid unnecessary care

Besides the concerns mentioned already, there are other reasons to avoid unnecessary care, including:

  • The discomfort or complications of testing. If you're needle-phobic, getting a blood test is a big deal. And while complications of noninvasive testing are rare (such as a skin infection from a blood test), they can occur.
  • The anxiety associated with waiting to find out test results
  • False reassurance that comes with false negatives (results that are normal or nearly so, suggesting no disease when disease is actually present)
  • All treatments have side effects. Even minor reactions — like occasional nausea or constipation — seem unacceptable if there's no reason to expect benefit from treatment.

The bottom line

You may believe your doctor wants you to continue with your current schedule of tests and treatments, while they might think this is your preference! It's worth discussing if you haven't already, especially if you suspect you may be taking pills or getting tests you don't truly need.

If your doctor says you can safely skip certain tests, treatments, and supplements, it doesn't mean that he or she is neglecting your health or that you don't deserve great health care! It's likely that the balance of risks and benefits simply doesn't support doing these things.

Less unnecessary care could free up resources for those who need it most. And it could save you time, money, and unnecessary risks or side effects, thus improving your health. It's a good example of how less can truly be more.

About the Author

photo of Robert H. Shmerling, MD

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

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