The heater is on. As the National Oceanic and Atmospheric Administration reports, 2018 is on track to become the fourth hottest year on record worldwide, surpassed only in 2017, 2016, and 2015. And that's just from January to June. So it's no wonder that it feels uncomfortably hot if you exercise outside or exert yourself in any other way - mow your garden lawn, for example.
But can being physically active in the heat also pose a risk?
In some cases, yes.
Most of the time, your body is good enough to regulate its internal temperature.
"The main way the body cools itself is through sweat," explains Michelle Cleary, Ph.D., associate dean of graduate programs at Chapman University in Orange, California. If you are not drinking enough to keep up with the fluid lost in sweat, however, your body can become overheated and dehydrated.
When you are physically active in these conditions, you can start to feel lethargic, dizzy, and even nauseous. In some cases, your temperature may rise, a possible sign of heat stroke, which can be dangerous, even fatal. According to a 2011 study, playing sports, exercising, and gardening were among the most common causes of heat-related emergency room visits.
And new research published in Plos Medicine suggests that heat-related deaths will increase. The study, which used a mathematical model to predict heat wave deaths in 412 communities around the world between 2031 and 2080, found that the number is likely to increase significantly in many areas.
According to the study, in the US, approximately 1,756 people die each year as a result of heat waves. In the future, researchers predict from about 2,400 deaths annually to about 10,400.
As health risks from heat increase, it's important to know how to stay safe, especially if you're active outdoors.
Dress well and protect your skin
What you wear can help you stay cool during a summer workout.
"You want to avoid anything that traps moisture against your skin," says Cleary. Opt for light, baggy items that allow sweat to evaporate more easily. Also, choose light colors, which absorb less heat than dark ones. Moisture-wicking polyesters can help keep sweat away from your skin, where it can evaporate and cool you down.
Also protect yourself from the sun's rays by wearing sunscreen with an SPF of 40 or higher during your outdoor summer workouts. Apply at least 15 minutes before going outside and reapply at least every 2 hours.
Not only does a sunburn increase the risk of skin cancer, but according to Luke Pryor, Ph.D., professor of kinesiology at California State University, Fresno, it can damage the sweat glands, which can hinder the ability of the body to cool down. .
Your body is about 60 percent water, which allows your kidneys to filter waste and your blood to transport nutrients through your system. Your sweat mechanism also helps keep your body at the right temperature, between 36.5 and 37 degrees.
How much water do you need? The Institute of Medicine recommends that men consume about 15 glasses of water a day and women about 11 (of non-alcoholic beverages).
However, rather than trying to keep track of your liters, Sandra Fowkes Godek, Ph.D., director of the HEAT Institute at West Chester University in Pennsylvania, recommends that you rely on your feeling of thirst to tell you how much water to drink. .
"Our thirst mechanism is adequate and very well developed," says Fowkes Godek. The exception to this guide is older adults. Our feeling of thirst diminishes as we age, so for older people, relying on thirst may not be enough to keep them hydrated.
As for what to drink, water is always better, says Fowkes Godek. We lose important nutrients known as electrolytes, such as sodium, magnesium, and potassium, through sweating. But most of us don't need sports drinks or other electrolyte-fortified drinks, as we can usually replace the nutrients that are lost in sweat through regular meals and snacks. Just as important, sports drinks often contain a lot of added sugars.
The exceptions: people who exercise for more than an hour at a time and workers who work long hours outdoors.
When it comes to food, consuming water-rich foods like cantaloupe, citrus fruits, and green leafy vegetables can help you stay hydrated. And while the heat can dampen your appetite, try having a small snack of about 150 to 200 calories per hour or 30 minutes before your workout, if you haven't eaten within the previous 4 hours. Then refuel in an hour after a workout.
Adequate hours for physical activity
During the summer, do most of your physical activity outdoors in the morning or evening, when it is a little cooler. When outside, stay in the shade as much as possible.
It's also important to let your body adjust to exercise or work in the heat, says Douglas Casa, Ph.D., executive director of the Korey Stringer Institute at the University of Connecticut, which produces research and advice on preventing related deaths. with the heat between athletes and workers.
That means, ideally, starting to work slowly up to a full intensity training session or a work day. A 2016 analysis found that taking eight to 14 days to acclimate to exercise or working in the heat may be more effective in minimizing heat stress on your body. But that is not always practical. However, if you have an outdoor activity, such as a big hiking trip, a long-distance run, or a major planned backyard project, try pre-working for a period.
Adults supervising groups of children, at camps or on sports teams, for example, need to make sure they also give young people a chance to adjust to the heat.
Symptoms of heat stroke
If you notice signs of dehydration or heat-related illnesses, such as dizziness or lightheadedness, headache, fatigue, nausea or vomiting, and muscle cramps, take a break from your activity, find the shade or a cool room, and drink water.
And keep in mind that while the ability to deal with heat and humidity varies from person to person, some weather conditions warrant precautions for everyone. So, pay attention to thermal advisories, advisories, and advisories in your area (available through the National Weather Service). On days with these alerts, take extra care to stay hydrated, and consider modifying your activity level or moving your summer workout indoors.
And watch out for signs of heat stroke, which can be fatal if not addressed quickly. The two most important symptoms are body temperature above 40 ° C and central nervous system problems, such as loss of consciousness, irritable or irrational behavior, mood swings, and disorientation.
You may not have a thermometer handy, but if you observe one or more of the above-mentioned behavioral symptoms during a summer workout in yourself or someone else, take action: “Lower your body temperature as fast as humanly possible. ”.
Have someone call 911 while you cool the person off. Get out of the heat and direct sun, and bathe in a cold shower or bath (or use water from a garden hose or any other available water if you can't get into the house). Turn on a fan or air conditioner to speed up cooling.
By Catherine Roberts
Original article (in English)