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Nutrition for the Heat

By Bob Seebohar

It’s getting warmer! Heat, sometimes combined with humidity depending on where you live, can throw you a good curve ball during these summer months of training and competition. We have all heard stories about athletes being taken to the hospital during a race for dehydration, or collapsing before the finish line or seeing white spots with a tongue feeling like sandpaper. I will say that those are extreme cases and ones that can be easily prevented with a little know-how nutrition for the heat know-how.

Sweat rate can increase up to 2-3 times in hot conditions. The risk of developing a heat illness increases dramatically and the body processes nutrients differently when the thermostat is turned up. All of these can lead to lousy training sessions or DNF’s during competitions.

Use the following nutrition recommendations to make your next quality training session or race in hot and possibly humid conditions a more successful venture.

Goal #1: Hydrate correctly. This is one of the toughest goals because it sounds so easy to do yet when it gets warmer, it is difficult to realize that fluid needs are increased. Add a little humidity so the evaporative cooling effects are less efficient combined with a higher sweat rate and this spells disaster for many athletes. I would argue that most DNF’s during summer month competitions are dehydration related.

Even though fluid needs will be higher, it is often difficult to consume more due to the heat, the shunting of blood and the body’s inability to process a significantly larger amount of fluid entering the stomach. When the body’s core becomes warmer, it effectively distributes the blood to the skin in order to dissipate the heat. This also redirects blood from the gut which can significantly impair your ability to digest and process the fluids you are drinking. If the environment is humid, it decreases the evaporative cooling mechanism as I mentioned earlier, which leads to a higher body core temperature which in turn leads to you not wanting to drink more to stay hydrated because you are either too hot to drink or because your stomach cannot process more fluids due to the reduced blood flow to the gut.

Either way, dehydration is inevitable. I would recommend beginning a pre-acclimatization process at least one month before competing in this type of environment. Wear extra clothes during outdoor workouts or travel and do some of your training sessions in a higher environmental stress. Using space heaters and a humidifier works well also if you cannot travel. Practice your normal fluid intake during these training sessions. Your body will fight it because it is hot but the best thing to do is to constantly remind your body of your hydration routine, even under this stress. It may also be necessary to increase your fluid intake if your sweat rate goes up significantly.

Goal #2: Use more electrolytes. With a higher sweat rate, typically – but not always – comes a higher electrolyte loss. If you fall into this category, there is not a sports drink on the market that will provide you the necessary electrolytes you need to replenish what you are losing. You should turn to using an electrolyte supplement (sodium, chloride, potassium, calcium, magnesium) with your higher electrolyte-containing sports drink. Choose supplemental electrolytes that have at least 200 milligrams per serving and add it to you sports drink. If you decide to take it by itself, be sure to have at least 6 ounces of water handy to wash it down.

Goal #3: Eat less but more frequent. With warmer temperatures typically brings two things: the craving for higher water-content foods such as fruits and/or a reduction in the feeling to eat. Hot environments typically induce a feeling of satiety in some athletes. This could lead to improper fueling strategies before or after a training session. Your best bet is to reduce the size of your daily meals and include 1-2 extra snacks throughout the day. By sticking to smaller portions that contain more water-dense foods, you will be able to keep your energy level stable and not feel like you have to eat even though you are not hungry. Chances are you will be hungry but your body is playing tricks on you due to the heat. It will be tough to do at first but it will eventually work!

Hotter, and more humid, environments pose a challenge to athletes, especially during training but can be easily navigated by following the steps that I have outlined. The important thing to remember is that you need more fluids, electrolytes and water dense foods but at more frequent intervals. As the thermostat goes up, adjust accordingly based on your training load and sweat rate.

Bob Seebohar, MS, RD, CSSD, CSCS is a sport dietitian and elite triathlon coach. He traveled to the 2008 Summer Olympics as the U.S. Olympic Committee Sport Dietitian and the personal Sport Dietitian for the 2008 Olympic Triathlon Team. He has served as head coach for Sarah Haskins, 2008 Olympian, was a performance team member (sport dietitian and strength coach) for Susan Williams, 2004 Olympic Triathlon bronze medalist. He is the current coach of Jasmine Oeinck, 2009 Elite National Champion.

Bob's new book, Metabolic Efficiency Training: Teaching the Body to Burn More Fat, will teach athletes how to structure their nutrition and training program throughout the year to maximize their body's ability to use fat as energy and improve body composition.  For more information and to order the book, visit or contact Bob at