Can We Determine RMR Based on Muscle Mass

The equation above is appropriate for inactive adults. However, for leaner, muscle muscular people such as athletes and fitness enthusiasts, estimating RMR based on body composition is more appropriate. The equation below is the Cunningham equation and uses fat free mass (FFM) to estimate RMR:

Estimating FFM is simple once percentage body fat has been determined (below). Begin by calculating fat mass, which is body weight times percentage body fat. Then subtract fat mass from body weight to determine FFM. Assuming our example man (82 kilograms, 180 cm) from above is also an athlete with 15 percent body fat, let's use the Cunningham equation to estimate his RMR:

step 2—determine FFM: 82 kilograms x 0.85 = 70 kilograms FFM

step 3—determine RMR: 500 + 22 (70) = 2,040 calories.

You see that the estimate of RMR is higher for our example man, using the Cunningham equation versus Mifflin-St Jeor equation, since he is more muscular than the average man and the Cunningham equation is based on fat free mass. The difference is largely skeletal muscle mass and condition.

Fitting Exercise Into A Busy Schedule

Fitting Exercise Into A Busy Schedule

Fit exercise into your busy schedule? Thats as absurd as saying that there are eight days in a week! First, youve never exercised before or engaged regularly in a sport second, youve never been into the fitness crowd and have had meager time for such pursuits, and third, youre far too busy to even think of exercise.

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