I have blogged about this subject before, but after a recent scary experience of near heat stroke, I decided to address it again.  As you all know, it has been a beastly hot summer so far.  And of course I decided to take a riding lesson on one of the hottest days (109 degree heat index).  I ALWAYS carry water with me and drink it constantly, so I was a little surprised to find myself overheated and faint after my ride.  Even worse was the migraine that followed and lasted the rest of the day.  Ironically enough, my July issue of Practical Horseman showed up the same day which happened to have a great article on staying cool and hydrated.  So, here is what you need to know about water, sweat, and signs of dehydration.


Why is Water Important?

  • It transmits heat produced by working muscles to the skin to regulate your body temperature
  • Water delivers oxygen to muscles and carries away waste
  • It helps maintain blood pressure
  • Water lubricates your joints
  • It carries moisture to your skin and eyes

Drinking enough water is important all of the time, but especially during sports and when it is hot out.  Sweating is your body’s way of cooling itself during exercise.  When your muscles generate heat, your core body temperature rises and your sweat mechanism is triggered. Sweat loss increases the concentration of sodium in your blood and causes your brain to trigger thirst.  Dehydration strains your cardiovascular system because the fluid lost decreases your overall blood volume, causing your heart to work harder.  When blood circulation is compormised, it is more difficult to maintain a safe core temperature.  As little as 1 percent dehydration can decrease performance. 


The most dangerous weather combination is high heat and high humidity, which we North Carolinians know all too well.  As sweat evaporates, it cools your body.  But when the air is moist, this process is less efficient.  So, an overcast, hot and humid day can actually be worse than a hot, sunny day with less humidity.  The good news is that as you become fitter, you will sweat more and faster over a greater surface area of your body.


Obviously, thirst is a good indication that you are not well hydrated.  Some other signs of dehydration are soreness, fatigue, muscle cramps, headache, dizziness, and reduced performance.  Drinking unconcentrated, clear fluids is best.  Water, non-caffeinated teas and sports drinks containing sodium and carbohydrates are good choices.  Have your drink cold if possible; it will empty out of your stomach and into your system faster.  Also, go ahead and gulp that water instead of just sipping it which also aids in gastric emptying.


I hope this helps everyone understand how important it is to stay hydrated while you exercise, or even if you are just hanging out in this extreme heat.  Stay safe and have a great summer!

Drinking unconcentrated, clear fluids is best.  Water, uncaffeinated teas and sports drinks are good choices.

Drinking unconcentrated, clear fluids is best. Water, uncaffeinated teas and sports drinks are good choices.

July 17, 2011 Kerri Davis