The following modifiers are gross values that include exercise expenditure and the base energy expenditure:
- Add about 0.13--0.16 calories per minute, per kilogram of body weight, for swimming. (For example, 0.16 calories/minute-kilogram x 60 minutes x 64 kilograms equals 614 calories needed for an hour of fast swimming.)
- Add about 0.15--0.17 calories per minute, per kilogram of body weight, for cycling. (For example, 0.17 calories/minute-kilogram x 60 minutes x 64 kilograms equals 653 calories needed for an hour of fast cycling.)
- Add about 0.14--0.29 calories per minute (roughly the range from an 11-minute pace per mile to a five-minute, 30 second pace per mile,) per kilogram of body weight, for running. (For example, 0.2 calories/minute-kilogram x 60 minutes x 64 kilograms equals 768 calories needed for an hour of fast running.)
- Add about 0.1 calories per minute, per kilogram of body weight, for strength training. (For example, 0.1 calories/minute-kilogram x 60 minutes x 64 kilograms equals 384 calories needed for an hour of strength training.)
The previous formulas estimate how many calories are needed to maintain your body as a "normal" person and as an athlete. These formulas work great for training, but it seems things change on race day.
On race day most athletes have butterflies fluttering around in their stomachs, so they tend to be less hungry. Butterflies, heat, altitude and multiple distractions can lead to under-fueling and under-hydrating. At the same time, over-fueling and over-hydrating can also lead to problems. What is an athlete to do?
- A good place to begin for race morning breakfast is to consume one to four grams of carbohydrate per kilogram of body weight one to four hours before the start of the race. If you eat four hours prior to race start, eat more than if you eat only one hour before race start. Some protein and fat in the pre-race meal works well for many athletes, but don't get carried away. The exact amount of fat and protein that can be consumed before race start seems to vary between individuals and may require some experimentation. Our 64kg athlete who eats four hours prior to race start, aims to consume around 256 grams of carbohydrate.
- During the race, a well-published guideline is to consume 30 to 60 grams of carbohydrate per hour of intense or long exercise--at minimum. Some athletes need to consume 350 to 500 calories per hour, such as athletes doing an ironman distance race. How much to consume depends on body size, pace, pre-event muscle glycogen storage and individual customization. This can be fluid or solid sources of energy.
- During the race, be certain to consume adequate fluids as well. Recent recommendations from experts give instructions to use thirst as an indicator of when to hydrate. For some athletes, utilizing thirst works well. Other athletes are better served by consuming fluids at a regular pace, tested multiple times in training, and adjusting that pace for race intensity, heat and humidity conditions. A good place to begin is approximately four to eight ounces of fluid every 15 to 20 minutes. An easy reminder during racing is to set a repeating alarm to sound every 15 to 20 minutes to remind you to eat and drink.
While the formulas can seem tedious, they do give you a place to begin your evaluation. They can help you outwit faulty body signals. When your body is saying, "I'm not hungry, I'm not thirsty" it may later say, "I'm not finishing this race" or "I feel so crummy, how about a trip to the medical tent?"
Just like physical training, nutrition requires strategy and planning. As you finish the most important races of the season, make sure there is enough fuel and fluids to propel you to a PR performance.