Hydration, Exercise and What to Drink When It’s HOT!

Can you believe the weather?  Of course you can.  El Nino fizzled out, and it’s Summertime in LA!  But you still have to exercise, right?  If it seems like you go into your workout already thirsty, you’re not alone.  But the age-old question remains:  do you use water or a sporIMG_3240ts drink?  How much of which and when?  What are the risks if you guess wrong or get caught in a fluid deficit situation? Here are some important tips for you whether exercising outdoors, indoors, or just outside, enjoying the day.

Understand that it takes your body about 10-14 days in a particular climate to become accustomed to the demands that that temperature will bring.  Our hormonal systems are complex, and the rhythms of regulating the balance of salts and fluids for our internal temperature change gradually.

A collection of heat-injury studies was reviewed by a group of exercise physiologists and physicians several years ago.  They found that the first four days an athlete was exposed to heavy exercise in an unfamiliar climate was far more influential for a heat-related injury (heat exhaustion, heat stroke) than the actual temperature or humidity!  So first, don’t jump into a strenuous outdoor program or event for more than 15-20 minutes if you are not used to being outside!

Secondly, fluids are as important as carbohydrates for an athlete’s performance, and much more critical to their health.  Since a loss of fluids in the central circulation does not immediately trigger a sensation of thirst, by the time you get thirsty, you are usually 1 1/2 – 2 quarts (liters) underhydrated!   Heat and humidity, types and amounts of clothing, and learning to drink enough of the right kinds of fluids are all challenges for staying hydrated.  To prepare for exercise, you should first know about how long you plan to go.  Listen to the advice from Dan Bernardot, Ph.D., nutritionist and exercise physiologist to top Olympic and professional athletes:

  • An hour before your exercise, drink 16 – 24 oz of a sports drink.
  • For endurance events < 30 minutes, sip water or sports drink – 4 oz. each 10-15 minutes.
  • For contests lasting > 60 minutes, sip 4 oz. sports drink every 10-15 minutes, and 10 – 12 oz.  at half-time or other breaks.
  • Find a drink that you like and will drink even when not thirsty.
  • Plan on drinking at least 3 quarts of fluids the day before your event; more if you have practice or the weather is hot.

I tell the football players that when they come off the field for a change in offense to defense, get two or three really big gulps before going back in.  At half-time, they are encouraged to have another sports drink before starting the second half.  The measure of whether the athlete has hydrated well is the color of urine following the event.  Light to medium color tells us that they had sufficient fluids to cool the body throughout the activity.

Here is a table of available of some of the drinks on the market.  For reasons too long to explain in this blog, I still prefer Gatorade.  However, any drink with similar percentages of carbohydrate and sodium should work as well.

Beverage % Carbohydrate Mg Sodium
Accelerade 7 127
Cytomax 8 10
Gatorade 6 110
PowerAde 8 55
PowerBar 7 160

Sports drinks are not healthy, however, for the unexercising.  Watching sports and drinking these beverages is not the same as participating.  The high sugar content can contribute to prediabetic influences and should not be a first choice at other times during the week.

Lastly, be mindful about the weather forecast.  With phone apps and news abundantly available, you shouldn’t be caught unprepared.  Here is a heat and humidity index I use when consulting with coaches and athletic directors about the suitability of training or playing outdoor sports.

If you are starting something new, outdoors and in the heat, start gradually; pre-hydrate the day before; wear loose, lightweight clothing; and start with 10-15 minutes, increasing your exposure slowly over a two-to-three week period.  Check your urine color later that day or evening to make sure you’re using enough fluids.  And if you have further questions about your particular needs, feel free to call the office for some free advice.  We’re always here to help!


One Comment

  1. Desi

    Thanks for the tips!! I have wondered if I should drink Gatorade, due to the sugar content, but it sounds like since I’m exercising. Thank you for the visuals and advice!!

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