Hydrate safely in the summer

Q: I’m a first time marathon runner, and I’ve been logging some pretty long runs in this hot weather. I don’t want to get dehydrated so I have been drinking a ton of water, but recently someone told I can drink too much water, is that possible?

—Jessica, 26, West Palm Beach, Florida

A: Congratulations on your first marathon! I feel for you though — this summer has been brutal for training outdoors. Last week, I had to walk halfway into my run because I just couldn’t take the heat — ugh! I caution all my kids who are in sports to replete their water losses before, during, and after long workouts. On hot days, athletes can lose about five liters or 20 cups of water through sweat during prolonged exercise (that doesn’t even count normal body losses). So it is vitally important to restore fluids.

But another thing that must be repleted is electrolytes — especially sodium. Excess water intake and sweat loss can lead to hyponatremia, more commonly called water intoxication. Hyponatremia can be caused by an underlying medical condition, ingestion of too much water without electrolyte repletion, or loss of sodium due to sweating, vomiting, etc. Basically, hyponatremia refers to a lower than normal amount of sodium in the blood. Without enough sodium, we cannot maintain fluid balance, regulate blood pressure, or perform normal functions of the nervous system. Drinking too much water without repletion of sodium tends to result in water entering the cells, resulting in swelling. When this occurs in the brain, it is referred to as cerebral edema and can be deadly. Symptoms of hyponatremia can include mental changes, headache, nausea and vomiting, tiredness, muscle spasms, and seizures. It is important when training to replete your electrolytes throughout your sessions. Here are some tips for staying well-hydrated this sweltering summer:

Before: On extra warm days, drink at least 16 ounces of water about 2 hours before exercise and about 8 ounces of a sports drink (like Gatorade) about 30 to 60 minutes before a long run. This combination may be partly responsible for reduction in urine production and in the retention of fluid, which can help to prevent dehydration.

During: Repletion of fluids, electrolytes, and glucose is important during prolonged exercise (anything greater than 1 hour). Drinking about 5 ounces of a sports drink or alternative with 4 to 8% carbohydrate (Gatorade, Accelerate, EFS, Heed and Coconut water, plain flavored for those who are trying to watch their weight) every 20 minutes can provide the proper amount of carbohydrate, electrolytes, and fluid. Start to refuel within 60-90 minutes of exercise and continue throughout as needed. Remember that unless you are training intensely for more than 1 hour at a time, a sports drink is probably not necessary.

After: Aim to drink about 20 ounces of fluid for every pound of body weight lost. (You can figure this out by weighing yourself before and then after your run). Also make sure to eat something that contains carbohydrate, protein, and sodium post workout within roughly 30 minutes to replete your glycogen stores. Take your time when eating to ensure adequate rehydration.

Go get ‘em!

** These are basic tips for prevention of dehydration and hyponatremia. For tips for optimal running performance, contact a sports nutritionist.