The idea behind working out, either with weight or doing cardio exercises, is to burn calories and increase fitness. The more calories that are burned, the more weight you can lose. This would seem to point to the idea that working out for hours a day every day is the most effective way to lose weight. That would be a wrong assumption, though.

How Long?

For exercise to be effective at all, it needs to be strenuous enough to raise your heart rate into the target zone for at least 20 minutes. The overall length of your workout should be 30 to 60 minutes in order to get the most benefit from it.

Heart Rate

To find your target heart rate, subtract your age from 220. This is considered your maximum heart rate. The American Heart Association recommends you keep your heart rate during exercise between 50 and 85 percent of your maximum heart rate. To find this range multiply your maximum heart rate by .5 and .85. If you have an intense exercise program you should expect your heart rate to be at the higher end of the range. The American Heart Association recommends working up to the high end of the range.

How Many Days?

There is a minimum number of days you should be working out to begin to see a benefit. Optimally, you should consider doing three to four days a week of aerobic exercise interspersed with two to three days of weight training or some form of resistance exercise.

Types of Exercise

Aerobic exercises include jogging, biking, swimming, vigorous dance and stair steppers. They are exercises that quickly elevate your heart rate, offer little in the way of resistance and cause you to breathe quickly. Resistance exercises include weight training or using rubber tubing for resistance. These exercises don't require constant exertion, but they do require you to work your muscles against a form of resistance.

How Soon For Results?

Depending on whether you reduce your calorie intake or not, you can see results in the first week of training. For every 500 calories more you burn or less you eat each day, you will see a pound reduction in your weight at the end of a week. Aim for two pounds a week. It's a reasonable goal.

Source:

About Aerobics.com

Diet Bites.com

American Heart Association