If you train to improve fitness for competitive or recreational endurance sports such as cycling, running, in-line skating, or triathlons, your success depends on developing solid nutrition and hydration habits to accompany your training plans. Quality training means maintaining a high speed relative to your effort. With dehydration or glycogen depletion, you slow down despite maintaining effort. That means you’re training to work hard while going slowly. This is not a skill most athletes want to perfect.
To keep training quality high, you must consume carbohydrate and fluids during any training session that is long enough to deplete you. It is okay to train to fatigue—but delaying that fatigue by eating or drinking will yield greater fitness gains.
What to drink?
Many drink products promise to improve VO2 max, increase endurance, and so on. Many of them work. Drinks that contain carbohydrate and electrolytes, and are diluted enough to allow you to properly absorb their components, all work about equally well. Powders you mix up or diluted apple juice with a tiny pinch of salt are equally good if they agree with your stomach. Research indicates that the most important quality of an exercise drink is having a taste that you like—so you will reach for the bottle and drink it. Water does not support endurance as well as exercise drinks when used alone, but when combined with carbohydrate-rich foods, water works great.
How much to drink?
Loss of any more than 1 percent of body weight (1 pound if you weigh 100 pounds, 1.5 pounds if you weigh 150) decreases aerobic power—which means decreased quality of training or decreased competitiveness in racing—so replacing the water that you lose through sweat or respiration is essential. Most athletes need between 16 and 50 ounces of fluid per hour of exercise. Water loss depends on individual body size, temperature, humidity, fitness, and other specific factors—so it’s impossible to subscribe precise values.
However, here are some guidelines to help you determine for yourself if you are drinking appropriately. If you guzzle water after a training session and don’t need to pee within the first 30 minutes after a session, pee dark, or lose more than 1 pound between pre-session and post-session weigh-ins, you’d get more from your training if you drank more.
If you gain any weight during a session or feel sloshy from water in your belly, you drank too much. Drinking too much is more dangerous than drinking too little during multi-hour sessions. As an athlete takes in water while sweating out salts, the salt level in the blood becomes diluted, resulting in a condition called hyponatremia. The extreme hyponatremia associated with gaining several pounds during exercise can cause coma and death, so don’t just keep drinking automatically and unconsciously while you exercise. Use the guidelines above to get the amount that’s about right for you, taking into account your current fitness and the weather. Take at least a gulp of liquid every 10 minutes throughout your exercise session. Think of short exercise sessions as practice for longer ones. The fact that you can finish a session without eating or drinking does not mean that you should.
What to eat?
Food eaten during exercise should be high in carbohydrates, easy to carry, easy to open, and easy to digest. Many athletes have success using fig bars, bananas, pretzels, boiled potatoes in a bag with some salt, a microwaved yam, small sandwiches, or energy bars (not protein bars). Experiment to find what works for you. Beginners and runners may find that they have a hard time digesting solid foods. They should consider using energy gels and they should definitely use an energy drink. Gels are also good for ultra-endurance events.
How much to eat?
During any exercise session longer than half an hour, begin eating at the half-hour mark and have a big bite of something every 15 to 20 minutes. Athletes in serious training or even moderately fit athletes cannot absorb as many calories as they expend while exercising. At best, they can slow their losses. If you wait until you’re hungry, your glycogen stores are already depleted. Aim to eat the maximum amount you can, before feeling full, while training. If you come home hungry you did not eat enough while training. If you come home full, you ate too much. Most exercisers will do best with between 175 and 325 calories per hour. Larger and more experienced athletes can eat more. Again, think of short workout sessions as practice for longer workouts and get in the habit of eating every 15 to 20 minutes any time you train.
Eating while exercising to lose weight?
If you are exercising to lose weight, diet at home, not while exercising. The surest way to derail a weight-loss exercise plan is to come home from your ride or run really hungry.
Remember: the better you can maintain your strength, the more calories you will expend while training.
