The peak summer heat and humidity is upon us. Workout intensity continues to increase. The AC at the office is broken. The ceiling fan is clicking on high.

As for maintaining thermoregulation, extreme environmental conditions bear an entire new level of difficulty (1). This is why we often hear of heat-

LONDON - MARCH 13: Students practice the unique Bikram Yoga at the City Studio, on March 13, 2007 in London, England. The Bikram Yoga, also known as Hot Yoga, is a style of yoga developed by Bikram Choudhury and is done in a room heated to 105?F (40.5?C), this helps stretching, prevents injury and makes the body sweat which aids detoxification. The class normally involves two breathing exercises and 26 postures in a 90 minute class. (Photo by Matt Cardy/Getty Images)

related illnesses during the summer (e.g. heat cramps, heat exhaustion, heat stroke).

As we discussed when busting last week’s sweat myth – our first adaptation to exercise is to sweat sooner.

Our bodies are pretty picky. They want to maintain a narrow homeostatic body temperature of 98.6 F.  When we exercise, several powerful physiological mechanisms of heat loss kick in to prevent an excessive rise in core body temperature (2)

Throw heat and humidity into the mix. This only adds to the challenge exercise already imposes on the human thermoregulatory system. Humidity is the equivalent of the skin’s worst sinus infection – congested with moisture from sweat with nowhere to go. With high temperatures present, the failure to dissipate internal heat causes the body temperature to rise even more. These conditions impair heat exchange between the body and environment. Pushing through the last set of prisoner push-ups is enough, now you’re forced to combat the heat too!

Good news – our body refuses to take ‘no’ for an answer. Give us heat, we take it on like a champ; adapting to deal with the environment wherever we go.

In just 10-14 days you’ve already adapted (most of which occurs in the first five days) (3)!

In the meantime, a few things happened making you better than ever …

  • Increase plasma volumes: No more hot temperatures taxing us as before (it’s hard work trying to stay at 98.6 F) AND we don’t require as much fluid (4)
  • Sweat earlier and faster: Less heat storage that would demand more fluid replacement (3)(6)
  • Reduce the amount of electrolytes lost in sweat: Remember, efficiency. We need these for other processes!
  • Reduce blood flow to the skin: Blood can go to other areas like your muscles…which trust me, you need (7)

The next brutal day when you’re hiking through the Pamulaklakin Forest, trapped in a house that feels like your college dorm from the ‘50s, and braving a lunch break power walk in a full suit – take your mind off the heat and embrace the changes your body is making.

You would feel much worse if you weren’t sweating…kind of like what happens when dehydrated…

Check back next week to see how it’s related!

References:

  1. International Olympic Committee consensus statement on thermoregulatory and altitude challenges for high-level athletes. M. F. Bergeron, R. Bahr, P. Bärtsch, L. Bourdon, J. A.. L. Calbet, K. H. Carlsen, O. Castagna, J. González-Alonso, C. Lundby, R. J. Maughan, et al. Br J Sports Med. 2012 September; 46(11): 770–779. Published online 2012 June 9. doi: 10.1136/bjsports-2012-091296
  2. Temperature regulation during exercise. M. GleesonInt J Sports Med. 1998 June; 19 (Suppl 2): S96–S99. doi: 10.1055/s-2007-971967
  3. Acclimatization strategies–preparing for exercise in the heat. Y. Shapiro, D. Moran, Y. Epstein Int J Sports Med. 1998 June; 19 (Suppl 2): S161–S163. doi: 10.1055/s-2007-971986
  4. Powers, S. K, Howley, E. T  (2012). Exercise Physiology: Theory and Application to Fitness and Performance. New York: McGraw-Hill Humanities/Social Sciences/Languages.
  5. Exercise in the heat: challenges and opportunities. Ron Maughan, Susan Shirreffs. Sports Sci. 2004 October; 22(10): 917–927. doi: 10.1080/02640410400005909
  6. Effects of training, environment, and host factors on the sweating response to exercise. L. E. Armstrong, C. M. Maresh. Int J Sports Med. 1998 June; 19 (Suppl 2): S103–S105. doi: 10.1055/s-2007-971969
  7. Control of skin circulation during exercise and heat stress. M. F. Roberts, C. B. Wenger. Med Sci Sports. 1979 Spring; 11(1): 36–41.

Written by COR Intern Amanda Presgraves