Research indicates that about 75 percent of American adults do not exercise and are overweight. While most people understand that lack of exercise can lead to fat accumulation, they typically are unaware of the physiological relationships that link inactivity and weight gain.

In addition to using fewer calories, inactive adults lose between one-half and one pound of muscle per year. This results in a lower resting metabolism that further reduces the calories utilized on a daily basis. Due to few calories being expended, even eating the same quantity of food causes weight gain. Dieting is largely unsuccessful because it generally results in more muscle loss and an even lower metabolic rate.

People need to understand that, for the most part, the problem of too much weight is really a problem of too little exercise. More than that, however, an exercise program must include strength training to replace muscle and restore resting metabolic rate.

The importance of strength training is illustrated in a study at Tufts University. After three months of basic strength exercise, the senior subjects added 3 pounds of lean (muscle) weight, lost 4 pounds of fat weight, raised their resting metabolism by 7 percent and increased their daily calorie intake by 15 percent.

But how much strength training is necessary, and how much time must be allotted for the overall exercise program? Because the majority of non-exercisers cite lack of time as their main reason for remaining inactive, a time-efficient training program would appear to be advantageous.

Most people in the fitness field consider a three-day-per-week, onehour-per-session exercise program standard for making significant improvements in body composition. The hour training session is typically divided into about 25 minutes of endurance exercise, 25 minutes of strength exercise and five minutes each of warm-up and cool-down activities. But studies show that a program consisting of less time can be almost as beneficial.

 

Two vs. Three Days Per Week

In a large research study, 716 previously inactive adults who performed 25 minutes of endurance exercise, 25 minutes of strength exercise and five minutes each of warm-up and cool-down activities three days a week for eight weeks experienced a 2.2 percent improvement in body composition. As shown in Table 1, they lost 4.6 pounds of fat weight and gained 2.5 pounds of lean (muscle) weight.

In the same study, 416 previously sedentary men and women performed the identical exercise protocol, but trained only two days a week. After eight weeks, they experienced a 2.0 percent improvement in body composition. As presented in Table 1, these participants lost 4.0 pounds of fat weight and added 2.2 pounds of lean (muscle) weight.

 

Table 1:

2 Vs. 3 Days