Summer is fast approaching here in the Northern Hemisphere, and you can bet that I am dying to take full advantage of the warm weather and spend time out in the sun.
And I’m not alone. The summer is the perfect time for everyone to enjoy what nature has to offer, relax in Central Park, or in my case, take my training and workouts outside. As a recreational baseball player who probably takes his rec league too seriously, I can’t avoid the outdoors; not that I mind, of course.
That being said, the sun should be treated just like everything else; it should be taken in moderation, and not in excess. Too much of a good thing isn’t exactly good after a while. There are going to be days this summer that will be oppressively hot, so much so that it would almost be better to stay indoors. On days like those, an extra dose of caution is a necessity if you insist on taking your physical activity outdoors.
If you’re like me and you’re adamant about spending as much time outside as possible, especially for any sort of physical activity, here are 3 things you should keep in mind to stay safe and beat the heat.
It’s OK to Sweat (A Lot)
The weather outside may change, but inside our bodies the weather should stay the same. Our bodies’ thermoregulatory mechanisms are primarily involved in maintaining body temperature at 98.6 degrees-Fahrenheit (37 degrees-Celsius). In the summer heat, their main job is to protect us against overheating.
Furthermore, evaporation provides the body’s major defense against overheating to combat the summer heat. This means that not only do you NEED to sweat, you WANT to sweat. Sweating during any physical activity in the summer is a good thing! And it’s not exactly the act of sweating that cools the body; it’s the fact that sweating brings excess body heat to the surface, allowing evaporative cooling to take place.
Evaporative cooling is enhanced by wet clothing or increased skin surface area. Getting your clothes drenched in sweat, or taking off your shirt actually enhances your body’s thermoregulatory mechanisms. This becomes a problem of course in activities that require a high level of skill, such as tennis or baseball. However, it is an absolute necessity. Moisture-wicking clothes become important here, not because they help you stay dry; but more so because they pull heat and moisture from the skin to the outside environment, allowing evaporative cooling to take place and keeping you comfortable in these physical activities. Staying dry is actually a bonus here.
Sometimes though, the body’s cooling mechanisms get overwhelmed. You can sweat all you want in extremely humid conditions; however, evaporative cooling is inhibited by those weather conditions (more on this later). Generally speaking though, it is OK to sweat (a lot). Finally, if you do choose to go the “half-naked” route, don’t forget your sunscreen; and find one that plays well with sweat.
According to one of my most important textbooks from my exercise science coursework: “adequate hydration provides the most effective defense against heat stress,” and “a well-hydrated athlete always functions at a higher level than one who exercises in a dehydrated state.”
The fluids you will lose through sweat don’t get replenished on their own. Staying hydrated during exercise in the heat is an absolute necessity, independent of all other factors. Stay hydrated, and avoid dehydration. Maintain electrolyte balance too, to avoid compromising your health and performance.
The amount of water you need is more than you think. According to McArdle, Katch, & Katch, you should drink:
- 17-20 oz of fluids 2-3 hours before exercise
- 28-40 oz for every hour of exercise
- 20-24 oz for every pound of body weight lost through sweat within 2 hours after exercise
That’s a lot of fluids. Additionally, replenishing your fluids with electrolytes and carbs helps you maintain performance as well. Sugar content notwithstanding, Gatorade is great during exercise. Stay hydrated, everyone!
Avoid Humidity and Know When to Stop
As I’ve been mentioning throughout this article, humidity is the one factor that we must always account for when we exercise outside, and perhaps the most dangerous.
Many of us have probably heard about how hot but dry weather conditions feel more comfortable than hot and humid weather conditions. Arizona may be hotter than Florida, for example, but I’m willing to bet that the desert conditions in Arizona feel way better than the tropical conditions in Florida. Of course, if it’s a 120 degrees, dry conditions don’t exactly make it safer to exercise outside. But humidity has a dramatic effect on our perception of heat and the body’s thermoregulatory mechanisms.
The table here shows the heat-stress index. You can see the dramatic effect that humidity has on air temperature, which causes the summer heat to feel way hotter than it should. Remember that humidity essentially slows down evaporative cooling; sweating is not as effective as it is in dryer conditions.
Here in the city, we get a mix of both humid and dry conditions. Before exercise, it’s especially important to take into account factors such as:
- your training experience
- you degree of acclimatization to summer conditions
- the clothing you’re wearing–are you wearing short sleeves or long sleeves? Light or dark clothing?
- and perhaps most importantly, the intensity of your exercise
These factors become more important in hot and humid conditions. If the combination of both temperature and humidity result in a heat sensation at or above 90 degrees-Fahrenheit, it’s probably a better idea to postpone your high-intensity interval training, or take it indoors at your gym.
Unfortunately, nearly 400 people die each year from heat stress here in the US, and many more suffer from its negative consequences. However, heat illness–which encompasses heat cramps, heat exhaustion, and heat stroke in order of increasing severity–is completely avoidable if you keep these 3 tips in mind. So go out there, enjoy yourself, and beat the summer heat by sweating, staying hydrated, and avoiding humid conditions whenever possible.
- McArdle, W. D., Katch, F. I., & Katch, V. L. (2010). Exercise physiology: Energy, nutrition, and human performance. Philadelphia: Lippincott Williams & Wilkins.
by Jeremy Lau
Jeremy Lau is a Senior Staff Coach at Halevy Life.
Jeremy graduated cum laude from Rensselaer Polytechnic Institute with a BSc. in Biomedical Engineering and received his Master’s in Exercise Physiology at Columbia University. In addition to his academic accolades, Jeremy is a Certified Strength & Conditioning Specialist (CSCS).
Prior to joining the team at Halevy Life, Jeremy completed a coaching internship at Cressey Sports Performance, where he coached both amateur and professional athletes, among whom were many professional MLB baseball players.
As an athlete, Jeremy has played baseball competitively for most of his life.