How Much Do You Have to Exercise for a Flat Stomach?

Calories are a measure of the energy you get from food. Weight gain is caused by consuming more calories each day than you expend. To lose 1 pound, you need to burn 3,500 calories more than you consume. By burning an extra 250 calories per day, you can lose a pound in just two weeks, or 2 pounds a month. To figure out how much exercise you need to do each day to lose weight, record the calories you consume and expend each day.

Use a journal to record what you eat and drink every day and calculate how many calories you're consuming. Record all physical activity you do each day for how much time and how many calories those activities burn. Or, you could wear a sports watch, heart rate monitor, pedometer or other device that more accurately measures how many calories you burn. At the end of the day, the calories you burn should exceed the number of calories you consumed. Reduce your caloric intake by opting for low-calorie foods like vegetables, whole grains and lean protein sources, and by keeping your portion sizes in check.

Cardio burns more calories than strength-training exercises. Some cardio exercises burn more calories than others. According to Harvard Medical School, running at 6 miles per hour torches 370 calories in just 30 minutes for a 155-pound person. For comparison, that's 110 more calories than high-impact aerobics and 35 more calories than the elliptical. Some strength-training exercises are more intense than others. Do compound exercises, like squats, deadlifts, bench presses, pushups and pullups, which work multiple muscles at once. These burn more calories and build more muscle in less time. Though you can't spot-reduce stomach fat, you should still do ab exercises, such as crunches, reverse crunches and planks. This way, defined muscles will enhance the appearance of your stomach as the layer of fat covering them disappears.

The higher your intensity, or the harder you work your heart and muscles, the more calories you burn. Intensity is measured not by speed or weight resistance, but by how much energy output the exercise requires. An effective way to measure intensity is going by the percentage of your maximum possible intensity, or the maximum heart rate you can reach during exercise. For example, exercising at 90 percent of your maximal intensity will burn more calories than exercising at 60 percent of your maximal intensity. To burn more fat in less time, incorporate high-intensity intervals into your cardio workouts. Do one- to two-minute bouts of intense cardio at 75 to 95 percent of your maximal intensity every few minutes while doing normal-paced cardio.

As a general guideline, the Centers for Disease Control and Prevention recommends doing at least 300 minutes of moderate-intensity exercise or 150 minutes of vigorous exercise each week if you're serious about your health and fitness. Vary the cardio exercises you do to challenge your muscles and avoid boredom. Do two to three strength-training workouts a week for a balanced program and to avoid losing muscle mass. If you're just starting to exercise, go at a steady pace to avoid injuries. Start with at least two and a half hours per week of moderate-intensity exercise like brisk walking.

Jürgen Schuster