Essentials of Nutrition for Sports

Schofield Equations

Estimate based on gender, age, and weight in kilograms:

Male:

Age 18-30:

Wt x 15.1 + 693

Age 30-60:

Wt x 11.5 + 1113

Female: Age 18-30:

Wt x 14.8 + 487

Age 30-60:

Wt x 8.1 + 846

Activity Energy Needs

Tables and formulae about the energy needs of various exercise

activities are approximate.

For example, the energy needed to ride a bicycle may be given

for 15 miles per hour. Are you riding a road bicycle or a mountain bicycle with wider, more road-resistant tires? Are you in an aerodynamic position, or sitting upright on a bicycle with grocery-store basket? Is there a headwind? Are you riding on level ground, climbing, or descending? Are you riding alone or in the slipstream of others? Based on Distance

One can only very roughly estim

ate the calories burned based on

distance. Cycling 1.^

For moderate road riding, you burn roughly 25 calories for every mile you ride, and 25 calories for every 100 feet you climb.

Double the burn rate for single-track mountain biking.

Burn rate is lower per mile

at slower speeds and higher per

mile at faster speeds.

Drafting reduces burn rate; upright bicycle position increases

burn rate.

Heavier riders burn more than lighter riders do.

2.^

Another method: calories used per hour = (0.046

x V

x W) + (0.066

x V

3 ), where V = velocity in miles per

hour, and W = weight of rider and bike in pounds.

By this formula, a 110-pound cyclist, riding a 20-pound

bike, and traveling at 12 miles per hour, would use about 186 calories per hour. A 150-pound cyclist, riding a 20-pound bike, and, and traveling at 12 miles per hour, would use about 208 calories per hour. Time trialing at 25 mph, a 150-pound cyclist would use about 1,200 calories per hour.

Running and Walking

Estimate calories burned as 1.1 calories per kilogram per

kilometer, or 0.8 calories per pound per mile. (These two estimates are close, less than one percent different.)

Weigh 60 kilograms (132 pounds)? Figure you burn about 660

calories running a 10K (6. 2 miles), or about 2,770 calories running a standard 42-kilometer (26.2-mile) marathon. Based on Perceived Exertion or Heart Rate

One can very roughly estimate caloric burn rates from exercise

intensity.

Assuming you weigh 60 kilograms or 132 pounds, are a

moderately-fit recreational rider, and are riding a road bicycle on level ground, you burn about 250 calories an hour riding easy (10 miles per hour, 60% of maximum heart rate), 500 calories per hour riding moderately (18 miles per hour, 75% of maximum heart rate), and 750 calories an hour riding hard (23 miles per hour, 90% of maximum heart rate).

For fitter riders, at a given speed, the burn rate will be similar but

the percent of maximum heart rate will be lower.

Heavier riders use more energy per mile than lighter riders do. Some heart rate monitors estimate calories burned. They provide

rougher estimates than those based on power, described below.

Nutrition for Sports, Essentials of 36