Summer Heat and Sun

2012 was the warmest year in U.S. history. The records started breaking in March, with a week of temperatures 18 degrees above average in much of the Midwest and Northeast. The next heat wave came in June. It was 105 degrees in Denver on June 25th, and 115 in Hill City, Kansas the next day. By the 28th, it was 108 in St. Louis, and on the 29th temperatures reached 109 in Nashville and 103 in Baltimore. With the summer heat came record-breaking drought and wildfires.

So far 2013 has been the opposite--much colder than average. But the trend is clear. Worldwide, each decade is hotter than the one before. We’ve learned how deadly heat waves can be, especially if you live in an old building in a city, or are poor, sick, or elderly. Now big cities broadcast warnings and set up cooling stations in libraries and community centers when the temperature gets dangerously high. It works--far fewer people in developed countries die during heat waves. No one wants a repeat of 2003, when 70,000 Europeans died in a blistering heat wave.

Heat isn’t the only summer health challenge. As Earth’s natural sunscreen, the ozone layer, gets thinner, the sun’s rays are getting more intense. We’re also living longer, so we tend to get more lifetime sun exposure. That means a greater risk of skin cancer. It’s already the most common form of cancer in the U.S. Do you know how to protect yourself and those you care for from too much heat and sun?

HEAT

How do our bodies cope with heat?

Your body’s #1 way to cool off is to expand the tiny blood vessels in your skin and send more blood there. It tries to transfer heat from your blood to cooler air around your body. But if it's over 90 degrees F (32.2 degrees C) outside, that doesn't work so well. It’s even less effective if you're sunburned.

At the same time, you sweat. But sweating only cools you if your sweat evaporates. That doesn’t happen as much if it’s humid. That's why humidity adds to the danger of high heat. As you sweat, essential salts pour out onto your skin. If you lose too much of these salts, your body is less able to keep hydrated and cool. If you can't keep your temperature normal via skin and sweating, your core body temperature begins to rise. That can lead to organ damage, and even death in severe cases.

Heat creeps up on us. You can protect yourself and those you care for if you take preventive steps. Know the symptoms of heat illness, and watch for them in yourself and others.

What makes high temperatures more (or less) dangerous?

• Humidity The “heat index” factors humidity in with temperature. Like the wind chill index shows how cold it feels, the heat index shows how hot it feels. So when it’s 90 in humid Miami, the heat index is much higher than when it’s 104 in dry Phoenix.
• Temperatures that are far above normal for the area Our bodies adapt to weather conditions where we live. We’re much more stressed when temperatures or humidity go far above those we’re used to.
• No access to air conditioning A/C is the best protection against heat-related illness and death. Even a few hours in a cool place helps your body cope.
• Exposure to direct sunlight This makes high temps more dangerous. People who must be outside are far better off in the shade.
• Housing that isn’t built for hot weather Some apartment buildings in older cities have black roofs, few windows and no central air conditioning.
• Air pollution Extreme heat and air pollution are a risky combination, increasing the strain on your heart and lungs. You can check on the air quality in your area in your local newspaper, TV or radio news or online at AirNow.gov.
• Drought or high altitude You may not realize you’re getting dehydrated when the air is bone-dry and your sweat dries almost instantly.

Who is at highest risk for heat-related illness?

• Infants and young children
• People aged 65 and older
• People with chronic health conditions like heart disease, diabetes, high blood pressure, obesity, or mental illness
• People who take certain drugs, including some tranquilizers, tricyclic antidepressants, antihistamines, medicines for Parkinson's disease, antipsychotics, blood pressure drugs, thyroid replacement medicines, and stimulants

Other conditions that increase risk include fever, dehydration, sunburn, social isolation and drinking alcohol.

What should I do during periods of extreme heat?

First, prepare for it by installing air conditioning and insulation if needed. Weather-strip doors and sills to keep cool air in. Install shades, draperies, curtains, awnings, or louvers on windows that get morning or afternoon sun. Outdoor awnings or louvers can cut heat by up to 80%. Once it gets hot:

• Stay indoors, in an air-conditioned place if possible. When the temp hits the high 90s, electric fans won’t prevent illness. If you don’t have A/C at home, go to a shopping mall, public library or public heat-relief shelter during the hottest part of the day.
• Drink cool, nonalcoholic fluids whether you’re active or not. Don’t wait until you’re thirsty. (If your health care provider limits the amount of fluid you drink or has you on water pills, ask how much you should drink while the weather is hot. Ask before drinking sports drinks that contain salt, too.)
• Avoid hot foods and heavy meals. They add heat to your body.
• Replace salts and minerals in your body with light food or sports drinks. Don’t take salt tablets unless you’re under medical supervision.
• Take a cool shower or bath.
• Wear lightweight, light-colored, loose-fitting clothing.
• Monitor people at high risk. Heat illness can make you get confused or lose consciousness. If you are age 65 or older, ask a friend or relative to check on you twice a day during a heat wave. If you know someone this age, check on them twice a day. A face-to-face check is better than a phone call. People suffering from heat often think they’re fine when they aren’t. Watch for signs of dehydration, heat exhaustion or heat stroke. Infants and young children, of course, need to be checked much more often.
• Provide plenty of fresh water in a shady place for your pets.
• Take time to adjust to changes in your environment. Any sudden change in temperature, like an early summer heat wave or travel to a hotter climate, stresses your body. Limit your physical activity until you get used to the heat.

If you must be out in the heat:

• Limit your outdoor activity to morning and evening hours if possible. Pace yourself if you’re not used to working or exercising in the heat. If your heart starts to pound or you get short of breath, STOP all activity. Get into a cool area or at least into the shade, and rest, especially if you get dizzy, weak, or faint.
• Cut down on outdoor exercise. If you must exercise, drink 2 to 4 glasses of cool fluids each hour. A sports beverage can replace the salt and minerals you lose in sweat. (Talk to your provider first if you’re on a low-salt diet.)
• Try to rest often in shady areas.
• Use a buddy system if you have to work in the heat. Monitor the condition of your co-workers and have someone do the same for you.
• Protect yourself from the sun. Wear a wide-brimmed hat and sunglasses. Use sunscreen of SPF 15 or 30 with broad spectrum UVA and UVB protection.
• NEVER leave people or pets in a vehicle, even in the shade with the windows open. Heat still radiates off the seats and dashboard. Half of kids who die in hot cars are left because parents forget they’re there. One way to remember is to keep a stuffed animal in the car seat whenever the child isn’t in it. Put the stuffed animal in the front seat when you buckle the child in to remind you there’s a child on board.

What are the warning signs of heat illness?

There are degrees of heat illness. Starting with the least severe:

• You get dehydrated with symptoms like thirst, very dry mouth or eyes, and skin that stays raised after you pinch it. Your urine is dark and concentrated, or there's very little of it. You may start to feel weak or sick to your stomach. You’re overdue for more fluids. Don’t drink anything with alcohol in it.
• You may get heat cramps, muscle pains and spasms if you’re exercising. Stop what you’re doing and get to a cool place. Drink clear juice or a sports beverage. Get medical attention if you have heart problems or are on a low-sodium diet.
• If symptoms worsen, you get heat exhaustion. Now you're sweating heavily, looking pale, and feeling tired and weak. You probably have a headache and may have muscle cramps. You may be dizzy, nauseated or vomiting. So much blood is going to your skin to try to cool off that your inner organs aren’t getting their share, and you’re in mild shock. You need to get into an air-conditioned place or at least into the shade, and rest and drink cool fluids. Cool your head and body with water or wet cloths. Take off any extra clothes. Get medical attention immediately if the symptoms are severe, you have heart problems or high blood pressure, or symptoms worsen or last longer than 1 hour.
• Without relief, heat exhaustion can become heatstroke. If someone has stopped sweating and their skin is red, hot and dry, or if they’re getting confused, it’s a medical emergency. Call 911. Other symptoms of heatstroke include a rapid pulse, throbbing headache, dizziness, nausea, unconsciousness and a body temperature over 103 degrees F (39.4 degrees C). While waiting for an ambulance, get the person in the shade and use cool water (shower, hose, tub, or cool wet sheets) to bring their body temperature down to 101 to 102 degrees F (38.3 to 38.9 degrees C).

My mother lives alone in another city. How can I tell when she's at risk?

Check the National Weather Service website at weather.noaa.gov to see if there are any advisories or warnings for your mother's area (or your own). You can also check the air quality online at AirNow.gov. It’s also a good idea to have the phone number of a neighbor in case you can’t reach your mother on the phone.

My son plays high school football, and I always worry about the preseason practices. Aren’t they dangerous if it’s hot out?

They can be. It’s important that coaches start slowly and let players get used to practicing in the heat for the first 2 weeks. The first week’s practices shouldn’t be over 3 hours a day, with just 90 minutes of fitness training. If it’s hot, players should wear light clothing with just helmets at first. Uniforms and other equipment should be added slowly. (That limits early practice to safer drills that don’t require it.) The kids should drink plenty of fluids and get a break every 30 to 45 minutes. Practice should be cancelled if it’s too hot and humid. It’s a good idea for players to have a physical exam before the season.

SUN

The picture of Hollywood glamour used to be a suntanned movie star in a bathing suit and sunglasses. But today’s actors avoid the sun to protect their skin from sun damage and wrinkles. If they look tanned, they probably use a sunless lotion.

Your looks aren’t the only thing at risk. Too much sun can lead to skin cancer. It’s the most common type of cancer in the U.S. Anyone can get it, but these things increase your risk:

• A lighter natural skin color
• Skin that burns, freckles, reddens easily, or becomes painful in the sun
• Blue or green eyes
• Naturally blond or red hair
• Unusual moles or more than 50 moles
• A personal history of skin cancer
• A family history of melanoma
• A history of sunburns early in life
• Frequent exposure to the sun through work, play, or location
• Indoor tanning (tanning booths or beds, or sunlamps) especially before age 35

Indoor tanning is so strongly linked with skin cancer that it’s illegal for minors in many countries. In the U.S., most states either ban it or require a parent’s consent. Some sunbeds put out 10-15 times more rays than you’d get midday in California. People who use them before age 35 have almost twice the risk of melanoma, the most deadly type of skin cancer. Indoor tanning is a hard habit to break for some people, so it’s best not to start.

There are three types of skin cancer. The first two are often called “non-melanoma” skin cancers:

• Squamous cell skin cancer grows on the surface of your skin in flat cells that look a bit like fish scales. It’s the most common type of skin cancer in people with dark skin. They often get it in areas that are not in the sun, like the legs or feet. People with fair skin more often get it on skin that has been in the sun, like the head, face, ears, and neck.
• Basal cell skin cancer grows within the top layer of your skin, usually in areas exposed to the sun like the face. It’s the most common type of skin cancer in people with light skin.

Symptoms of basal cell and squamous cell skin cancers include a new growth, a sore that doesn’t heal, or a change in an old growth. You might have:

• A lump that is small, smooth, shiny, pale, or waxy
• A lump that is firm and red
• A sore or lump that bleeds or develops a crust or a scab
• A flat red spot that is rough, dry, or scaly and may become itchy or tender
• A red or brown patch that is rough and scaly

Non-melanoma skin cancers can almost always be treated successfully. The cancerous area may be burned, cut off, or treated with chemotherapy that’s applied to the skin. That may leave a scar, especially if the cancer is wide or deep. If you have badly sun-damaged skin your may need a series of procedures.

Melanoma is the most serious type of skin cancer. It causes nearly all skin cancer deaths. It begins in the pigment cells that make your skin darken from sun exposure. It can occur on any skin surface, but in men, it’s most often on the head, neck, or torso (between the shoulders and the hips). In women, it’s often on the lower legs or torso. People with dark skin rarely get melanoma.

The first sign of melanoma is often a change in the shape, color, size, or feel of an existing mole. Or it may appear as a new mole. Think of “ABCDE” to help you remember what to look for:

• Asymmetry: The shape of one half of the mole doesn’t match the other half.
• Border that is irregular: The edges are often ragged, notched, or blurred in outline. The pigment may spread into the surrounding skin.
• Color that is uneven: There may be shades of black, brown, and tan. You might also see areas of white, gray, red, pink, or blue.
• Diameter: The size of the mole has changed (usually it’s bigger). Melanomas can be tiny, but most are larger than the size of a pea (about 1/4 inch).
• Evolving: The mole has changed over the past few weeks or months.

About 4 out of 10 melanomas are found when they’re small and thin, and haven’t spread beyond the skin. If they’re removed, the cure rate is nearly 100%. Melanomas that have spread may require surgery, chemotherapy, and radiation, and can be fatal.

If you notice changes in your skin, get evaluated by your provider.

I heard that it's good to get some sun on your skin without sunscreen because it gives you vitamin D.

Our bodies make vitamin D from sunlight on our skin, or we can get it from fortified foods like milk or supplements. Many of us (especially people with darker skin and those who don’t go outside much) have low vitamin D levels.

If you haven’t had skin cancer, and aren’t at high risk, you can build up your vitamin D levels by exposing your skin to sun without sunscreen for a few minutes on a few days each week from spring through fall. Five minutes is plenty if you’re fair; the darker your skin, the longer you may need. The more skin you expose, the less time you need. Or you can take a vitamin D supplement. The upper limit for people over 9 years old is 4,000 IU of a day.

How should I protect my skin from the sun?

• Stay indoors or seek shade during midday hours (10 a.m.to 4 p.m.) when the sun’s rays are strongest and do the most damage.
• Cover up with clothing to protect exposed skin.
• Get a hat with a wide brim to shade your face, head, ears, and neck.
• Wear wraparound sunglasses that block nearly 100% of both UVA and UVB rays.
• Use sunscreen with sun protective factor (SPF) 15 or 30 with “broad spectrum” coverage from both UVA and UVB rays. Put on a thick layer 30 minutes before you go outside. Apply it again every 2 hours or after swimming or sweating. And don’t rely only on sunscreen alone.

When is sunburn dangerous? How should it be treated?

Sunburn is never good because it damages and ages the skin, and can lead to skin cancer. Get sunburn evaluated by a health care provider:

• In an infant under one year old
• In anyone with a fever, extensive fluid-filled blisters, or severe pain

Treat sunburn with cold compresses, or put the sunburned skin in cool water. Apply moisturizing lotion. Don't use salve, butter, or ointment. Do not break blisters--and stay out of the sun!

I damaged my skin by tanning constantly when I was young. Is there anything I can do now to improve it?

The prescription drug tretinoin (Renova and Retin-A) can help reverse sun damage. It’s a cream that you apply to your face, neck and hands. It improves the texture and color of sun-damaged skin, and reduces freckles and wrinkles. It can make your skin red and irritated. It can also make you more sensitive to the sun. You must use sunscreen and avoid the sun if you use tretinoin.

As our climate changes, extreme weather is becoming the “new normal.” Protect yourself from heat and sun so that you can enjoy this summer and many more to come.

Updated on 4/18/2013 by Jennifer Johnson, BA English composition, Northwestern University. Reviewed by Steve Silverstein, MD. Published on 5/20/2013.

References:

1. Extreme Heat. http://emergency.cdc.gov.
2. Skin Cancer Awareness: Protect Your Skin. www.cdc.gov.
3. What You Need To Know About™ Melanoma and Other Skin Cancers. www.cancer.gov.
4. Heat Waves Are Heart Breakers. MedPage Today. September 18, 2012. www.medpagetoday.com.
5. 2012 among the 10 warmest years on record, figures show. www.guardian.co.uk.
6. Pawlak MT et al. Legislation restricting access to indoor tanning throughout the world. Arch Dermatol 2012 Jul 16. Abstract.
7. Nancy Walsh. Melanoma on Rise with Indoor Tanning. www.medpagetoday.com.
8. Chagpar AB. Some melanoma survivors still use tanning beds; Sun protection practices among melanoma survivors: AACR 2013; Abstract 1365.
9. Study Affirms Indoor Tanning, Skin Cancer Link www.medpagetoday.com.

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Page last updated: May 17, 2013