Because this issue is focused on a healthy you for the coming year, we thought we’d address the role of exercise in fat loss, and in the process explore the relative effects of resistance training and aerobic training in attaining and maintaining proper weight control.

That magic word Metabolism. The sum of all chemical and physical changes that take place within the body. If you’re blessed with a ‘fast’ metabolism, weight control is not a problem. But most people seem to have a metabolism that is stuck on ‘slow’. The truth is that people are not generally born with their metabolic thermostat set on low - they gradually change the setting themselves. And the good news is that even if you do have a slow metabolism, you can rev it up to fast!

Most people are at least somewhat attuned to the idea that proper nutrition has a definite effect on your metabolic rate. But the one single element that can change your metabolism from sluggish to super charged is exercise!

It is a fact that the sedentary lifestyle most Americans follow today is a major contributing factor to the condition of being overweight. Turn this fact around and you get a simple formula: Increase your activity levels - Decrease your body fat.

Studies comparing the effects of diet and exercise on body composition indicate that, if forced to choose one modality or the other, exercise is a better means of losing body fat than dieting. Why is proper exercise so vital for proper weight control? Let’s take a brief look at a few of the good things exercise does for us.

*Exercise burns calories. This simple fact helps balance the ‘Energy In’ (food and beverages) versus ‘Energy Out’ (physical activity) equation.

*Exercise burns fat as an energy source.

*Exercise boosts your metabolic rate from 3 to 8 times normal. This means that even after exercise your body burns calories at a higher rate than usual for up to 24 hours.

There are two basic categories of exercise: aerobic and anaerobic.

Aerobic exercise is essentially low intensity, long duration exercise designed to improve circulatory and respiratory function, i.e.- the ability or capacity to take in, transport and utilize oxygen. Commonly used examples of such exercise would be walking, jogging, bicycling and aerobics exercise classes, though any physical activity that satisfies the exercise intensity/frequency/duration parameters will result in cardiovascular/cardiopulmonary function. A basic overview of the intensity/frequency/duration parameter is as follows:

*Intensity: Aerobic exercise intensity, or degree of effort, is commonly measured in terms of target heart rate, or percentage of maximum heart rate.

*Frequency: Aerobic activity should be performed between three and five times per week. Less than three times per week does not produce desired effects for fat burning or for improving cardiovascular function, while exercising every day without “off” days can lead to overtraining (usually the cumulative effect of micro trauma to the knees, lower back, ankles, etc).

*Duration: Each workout session should be between twenty and sixty minutes. Less than twenty minutes of continuous activity does not produce the desired fat burning effect nor does such a time period stimulate cardiovascular function to a pronounced degree.

Anaerobic exercise is essentially high intensity, shorter duration exercise. Examples of anaerobic exercise activities include sprinting, wrestling and conventional weight training (we use the term ‘conventional weight training’ to differentiate from circuit training, in which the trainee moves from exercise to exercise or station to station with only a few seconds rest between each, or advanced training techniques that involve few brief rest periods between sets, which techniques, given the proper duration factor, cause a crossover in the aerobic/anaerobic thresholds and pathways).

The primary example of anaerobic exercise is weight training, resistance training or strength training, all words that describe the same type of activity - in which muscles are required to contract against an opposing force (free weights and/or machines). Contrary to what many people think, strength training is as important, maybe more important, to successful fat loss than aerobic exercise. The reason lies in the amount of calories that are burned when you aren't exercising. Depending on the intensity and your weight, an aerobic workout (walking, cycling, stair stepping) will burn approximately 300 calories per hour. If the exercise is strenuous enough (which is unlikely in the beginning exerciser) the Resting Metabolic Rate (RMR) will be elevated temporarily up to a few hours afterwards. Compare this to strength training which elevates the RMR permanently.

The RMR accounts for 60 to 75 percent of your daily calorie expenditure, so even a modest increase will help burn off more fat. One study (Campbell 1994) found that a three-month basic strength-training program resulted in the subjects gaining three pound of muscle and losing four pounds of fat, while eating 370 more calories per day (a 15 percent calorie increase). Remember, aerobic exercise generally doesn't increase muscle tissue. In fact, excessive amount of aerobic exercise combined with a low-calorie diet can cause the loss of some muscle tissue. This is not to say that overweight individuals shouldn't do aerobic exercise--it offers many health benefits and is a part of a weight loss program. It's just that aerobic exercise by itself may not be the best solution for permanent weight (fat) loss. Another important benefit of resistance training is that it conserves protein stores, and thus lean mass, in the body during weight loss while dieting is normally accompanied by a loss of lean tissue (muscle). Because metabolic rate and energy expenditure levels are related to the amount of lean muscle mass in the body, the body burns less fat as muscle mass is lost…this is where the permanent elevation of RMR comes in.

It makes no difference whether you’re a male or female - losing muscle is a bad thing. Muscle tissue is very active--it burns a lot of calories. Every pound of muscle burns between 35 and 50 calories per day. Translated, that means if you lost 4 pounds of muscle, you would be burning between 140 and 200 calories less per day, or between 4200 and 6000 calories less per month. Since there are 3500 calories in a pound of fat, you would gain well over a pound of fat per month just from the muscle mass that you lost! Conversely, if you gained just 4 pounds of muscle, which evenly distributed over a female physique will simply give the feminine physique a ‘toned’ and shapely look, you would lose over a pound of fat a month simply because of the metabolically active lean mass!

Of course, the best route is to combine anaerobic and aerobic exercise with proper nutrition, thereby attacking both causes of overweight – excess energy intake and inadequate energy expenditure.

In addition to aiding in weight control, exercise strengthens the heart, improves lung function, reduces the risk of diabetes and high blood pressure, builds stronger bones, muscles, and joints - and combats stress and promotes psychological well-being. In essence, exercise makes you look better and feel better. Every time you exercise you’ll be burning fat, losing unwanted pounds and inches, and looking and feeling better and younger - all at the same time!

Arley Vest