One of the most interesting comments I hear as a trainer is, “I am so out of shape!  I sweat so much!”  The reason why I find this comment interesting is because you actually sweat more the MORE in shape you are.  Like I have said before the body is a stupid machine.  It can control a lot of variables, but how it knows whether to turn a response (such as sweating) on or off is very similar to a simple home thermostat.  When our core temperature rises (by doing work such as exercise) receptors in our body signal our bodies to start sweating.  Those who exercise on a regular basis stimulate these receptors frequently therefore, they are more likely to respond sooner at the onset of exercise.

• This is one reason why it is important to warmup properly for exercise.  If you can gradually raise you body temperature, you will start sweating before your core temperature rises too high leaving you feeling uncomfortable.

As you can see from the pictures above, as we begin exercise the majority of our blood flow shifts from the organs to the muscles.  (One reason why it isn’t a good idea to eat a big meal before exercise.  If there is no blood in your digestive tract that food will just sit there and be more likely to come back up!)  If you have been training for a while and are good about your fluids, look back to A little Physiology Lesson: http://wp.me/p29mJ2-9S , you will to have enough blood to not only supply working muscles, but also profuse the capillary beds on the outer layers near your skin.  This will allow your pores to open up releasing more sweat then your less active friends because you have fluid to spare.  As you sweat, water molecules forming on your skin with the most energy will evaporate off your body leaving the cooler beads of water with less energy to cool your skin.  (This is a not so complicated chemistry principal, but most people didn’t enjoy conversion factors and chemical principles like I did so just take my word for it 😉 )

Moral of the story, sweat is your friend!  It helps keep your core temperature lower so you can work harder!  And don’t bother wasting energy wiping it!  1. This will actually make you hotter and 2. It will just come back!

Final take home message, make sure to replenish your fluids.  If you sweat out all your expanded blood volume you will not have the same benefits during your next workout.