During the summer, the gym usually quiets down as weather heats up. Running and biking outdoors trumps being stuck inside on a treadmill. However, this trend may be shifting. See why.
More people are in the gym this summer. With record-high temperatures and longer duration of heat waves, it is, of course, much harder to exercise outdoors and be comfortable. Not only that, but it can be downright dangerous. The National Association of Athletic Trainers in a position statement released in 2014 stated that “heat stroke from exercise is one of the three leading causes of sudden death in sports activities, with heat-stroke deaths rising between 2005 and 2009 to higher rates than observed in any other five-year period during the past 35 years.” There were an estimated 20 to 22 deaths from 2010 to the date of the publication just 4 years later1.
There is clearly a trend toward increased heat-related illness and death, and perhaps a correlation between this and weather. A research and public education group, Climate Central, recently released a report about the impeding surge in extreme weather, including heat-related “danger days.”2 This term describes what happens when weather conditions are so extreme that it is not safe to be active outdoors. This is particularly significant for athletes and youth sports participants, along with anyone who participates in outdoor exercise. Danger days are defined as when the “heat index” (a combination of temperature and humidity) reaches 105◦, which is the temperature at which the risk of heat exhaustion becomes a major concern.
A slightly less serious condition is called the “extreme- caution” category. At a baseline of 90◦ a major concern is that most people will begin to suffer muscle or stomach cramping. However, children, the elderly and anyone with compromised health conditions are still at risk for heat exhaustion at this level. Climate Central predicts that by the year 2050, several states (mostly in the southern part of the U.S.) will experience a serious increase in number of danger days. For example, using yearly averages from 2010-2019, Corpus Christi, Texas, has 1.3 days with a heat index 105◦ or higher. By the year 2025 that number is projected to increase to 125.
Heat exhaustion mainly presents itself as a combination of symptoms, such as fatigue, disorientation, headache, cramping, fainting, increase in heartrate, and change in sweat rate (which lessens when the humidity level reaches 60% - where sweat is no longer effective at cooling the body). It can progress and worsen to become a heat stroke, which is serious and life-threatening.
Not a lot can be done to change the weather – whether or not climate change is to blame. Extreme outdoor temperatures should be taken seriously.
There are many precautions that can be taken, starting with “acclimatizing” or “easing” into activity in a hot environment. The National Athletic Trainer’s Association gives specific guidelines about how to do this, including taking one to two weeks to become accustomed to activity in hot weather and shortening work periods while adding longer rest periods in between. Staying hydrated is key with plain water being the preferred beverage. Go by the color of urine as an easy guideline – with a “straw” color indicating a good level of hydration. Dark color is not a good sign! Recommendations vary by each individual’s needs, depending on size, level of activity, etc. but in general drink at least 8-16 oz 2 hours before activity and then sip (vs. “guzzling”) fluid during exercise. Weighing in before and after exercise can help determine how much fluid to replace sweat loss with – with reduction in 3% or more in body weight post-activity significantly increasing the risk of heat exhaustion. For each pound of body weight lost, consume 16-24 ounces of fluid no more than 30 minutes afterward. Care must also be taken not to “overhydrate” so try not to drink any more than you have to – you can’t put it “in the bank” to be used later! Symptoms of over hydration (or hyponatremia) can mimic those of heat exhaustion. Check with a nutritionist to help determine your specific needs!
Other techniques you can use to “beat the heat” include wearing moisture-wicking, sun-protective clothing, which is widely available in sporting goods stores for outdoor sports enthusiasts. Except where the humidity levels are high (in mid-west and southern states) exercising early in the morning or later in the evening can help mitigate heat effects.
Lastly, when the heat outside gets dangerous, it would be best to avoid going out there altogether. It would be worthwhile to invest in a gym membership where you can be inside an air-conditioned environment. I know that I feel much better doing that – I have spent many times exercising outdoors feeling borderline heat-sick. It is not worth it!
Although the predicted future sounds bleak – we can still adapt as best we can. By following precautions and staying aware of what is going on in our environment, we can still take control of our potential.
[1] http://www.nata.org/sites/default/files/Heat-Illness-Executive-Summary.pdf
[2] http://www.climatecentral.org/news/danger-days-on-rise-in-us-cities-19322
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