Whether you want to show off in a bikini or set a great example for your kids, exercise is a crucial component for health. Although this is a given considering past decades of scientific research on weight loss and physiology, not everyone understands just how much time in the gym is essential. You might not need to put as much effort into the weights or treadmill as you thought.
To really get how much time you should be exercising, you first have to look at your basal metabolic rate, or BMR. This is the amount of energy (calories) you burn at rest and which your body uses up just surviving. The basic rule of thumb is that you absolutely must net at or above your BMR in terms of caloric intake. This means that, when you subtract the amount of exercise calories you’ve burned from your total calories for the day, the difference is at least what your body needs to support fundamental physiological processes.
Why BMR Matters
When you are trying to exercise and eat right to lose weight, netting at least your BMR is non-negotiable because your body eventually will think you are starving if caloric intake isn’t meeting energy requirements. As the body tries to figure out how to deal with the perceived starvation, it can use stored carbohydrates, fat or protein for energy sources. Protein is what makes up lean muscle mass. Normally the body uses metabolizes muscle as a last resort, but lean muscle tissue requires more calories than other tissue. The body will metabolize muscle as a way of reducing the number of calories you need per day. That’s hardly what someone looking to get ripped wants, and it can be especially dangerous considering that one of the most vital organs of the body—the heart—is a muscle. The heart actually can decrease in size, slow and eventually fail. As your metabolism slows and you lose lean muscle, it becomes harder and harder to eat “normal” amounts of calories without gaining weight, simply because you’ve trained your body to make do with less and to hang on to anything “extra.”
American College of Sports Medicine Recommendations
The American College of Sports Medicine takes BMR requirements seriously because of the potential dangers of insufficient caloric intake. Subsequently, they endorse a minimum net daily caloric intake of 1,200 for women and 1,800 for men. Factors such as age and height affec