Sweating, Hydration and Exercising in the Heat

Credit: Flickr/Manoj Damodaran

Exercising in the heat requires you to pay attention to your hydration

The hot weather is finally here but that doesn’t mean you can’t stay active in the heat

You’ll certainly sweat a lot more when it’s hotter outside, but that doesn’t mean you should simply drink a ton of water to stay hydrated. As I’ve previously written about staying hydrated in the heat, drinking too much can cause severe problems, as can drinking too little.

Drink According to Your Thirst

“Drink lots of water” is advice you might hear when you’re working out in hot, humid conditions.

But according to Tim Noakes, MD, DSc, one of the leading authorities on sports hydration and author of the book Waterlogged, too much water can cause a serious imbalance in the body. Over-hydrating can lead to a condition called hyponatremia, in which sodium levels in the blood are diluted too much causing excessive stress to the cardiovascular system. Severe cases can result in death as demonstrated by a handful of deaths in marathons over the past decade.

This doesn’t mean you shouldn’t drink at all, but Dr. Noakes recommends using your thirst as a guide. Don’t let yourself get too thirsty before drinking and you should be fine.

Sodium and Hydration

The other issue when exercising in hot conditions is the amount of sodium you’ll lose through sweating. Sodium is the most important of all the electrolytes, so you should be replacing some of the sodium lost. (Electrolytes are minerals that perform vital physiological functions).

Instead of drinking plain water, choose a sports drink that contains sodium and possibly other electrolytes. You can also use electrolyte tablets and simply drink those down with plain water.

Is Coconut Water Effective?

Coconut water is being hailed as a miracle beverage since it naturally contains electrolytes. Real, 100% natural coconut water does contain a full spectrum of electrolytes including 252 milligrams of sodium per one cup serving.

However, commercial coconut water products often contain far fewer electrolytes than pure coconut water. And a ConsumerLab.com test showed that two of the three products tested didn’t even contain the amount of electrolytes listed on their labels.

So coconut water may be a good beverage to drink throughout the day but when exercising I’d suggest using a sports drink or electrolyte tab that contains more sodium.

Individualize Your Hydration

Because people vary so much in their sweat rates, exercise intensities and the length of their workouts, it’s difficult to provide general recommendations on how much to drink. The best thing to do is to individualize your hydration to your specific needs.

A free and easy way to do this is to use an online exercise hydration and nutrition calculator developed by sports scientist Dr. Robert Portman. In addition to giving you a good guideline on how much to drink, it will also provide you with information on how many calories to eat during and after exercise.

If you’re looking to find out your specific sodium needs, check out the H2Pro Hydrate system. Using a non-invasive medical testing procedure you can find out your individual sweat rate. Based upon this you’ll use a specific concentration of dissolving tablets to put into your water bottle that will contain the amount of sodium you need. There is a fee for the test but you’ll have accurate information on what your body needs.

I’ve had the H2Pro test done and tested their products on myself. I actually prefer it to other electrolyte products I’ve tried and it’s the drink I’ll be using at the Knee Knacker this Saturday. It looks like it’ll be a hot day and I’ll be out on the trails for six to seven hours, so keeping my sodium levels from dropping too much is an important factor in finishing the race.

Hydration Tips Summary

Stay active in the heat but remember these tips:

• Drink according to your thirst or use the Portman Calculator to determine your hydration needs.
• When exercising for longer than one hour, don’t drink plain water but use a sports beverage or tablets that contain sodium.
• If you’re a competitive athlete or even a recreational level athlete who wants to perform to your potential, consider getting your individual sweat rate tested and then use a drink with the specific sodium concentration you need.
• Have fun in the sun and DON’T complain about the heat! Remember, most of our year is cloudy and grey so enjoy the natural vitamin D.