It's science issue for this column! I like to take a question or comment from a client every so often and use it for my topic. Since it has been amazingly hot recently, I heard a lot of people (rightfully so) complaining about the humidity and how uncomfortable it makes them. . . especially during exercise. So, one day I asked a client if she ever wondered specifically why high levels of humidity are unbearable with physical activity. She looked at me a bit confused; her expression was saying "It just is." So, I thought I would take the opportunity to explain just that.

Back in college, I loved the class Exercise Physiology, because it explained SO many things that we just accept at face value. . . such as why we get sore, why some people get light headed during exercise, why high humidity stinks, why fitness can plateau, etc. That class truly gave me the appreciation for how the body reacts (or doesn't) to activity and has abundantly helped me with my job and curious clients. So. . . back to my original topic.

When you exercise, your body warms up and your body temperature increases. The body is amazing at self-regulating temperature, and when your temperature rises, your body's cooling mechanism kicks in. The body re-directs blood from the deeper, more central parts of the body, like the internal organs, to your muscles and into the blood vessels that are closest to the surface of the skin causing you to sweat. Sweat is the body's main mechanism to cool the body and is comprised of water and salt. It exits the body via the pores in the skin and when the air evaporates the water, the underlying blood is cooled.

Therefore, if the air surrounding the body is humid, sweating becomes a less efficient way to cool the body. The higher the humidity, the less efficient sweating is. You know how when it's quite humid you are soaked in sweat? That is sweat, sitting on your skin, unable to evaporate. It doesn't evaporate because the air is already so saturated with water. When sweat can't evaporate, it doesn't cool off the body. Sweating in and of itself does not cool the body. . . so using a towel to wipe off sweat (while might be appreciated by others at the gym) does nothing to cool you. The body keeps pumping out sweat, but the body temperature does not drop.

Because of this, exercise at any given level seems harder, but the muscles actually aren't working any harder. And the heart has to work harder due to less water in the blood. So not only is the sweat not being evaporated to cool you but your heart is working overtime.

Excessive heat and humidity can often lead to elevated body temperature, dehydration and electrolyte imbalance. Which in severe cases can lead to an array of health problems. This link is a helpful resource for help with humidity during exercise and cooling the body: http://www.mayoclinic.org/healthy-lifestyle/fitness/in-depth/exercise/art-20048167

I know this may seem like an odd time of year to write this one as the cooler temperatures are coming, so save this one! Or I may just have it reprinted