When you work out, your body gets the energy you need for sustained activity by burning your stored calories. When you perform aerobic exercises, your body keeps burning calories for a short time after you finish your workout. When you perform strength-training exercises like weightlifting, you permanently boost your calorie-burning capacity by increasing your body's supply of muscle tissue.
Aerobic Exercise Effects
Aerobic exercises such as swimming and cycling trigger calorie burning by making you move your limbs repeatedly for relatively extended periods of time. Low-intensity activities like walking make you burn off a fairly small amount of extra calories, while a high-intensity activity like running can make you burn off more than 1,400 calories in a single hour. After you finish an aerobic exercise, your body gradually returns to its normal level of calorie usage. For experienced exercisers who engage in high-intensity activities, heightened calorie burning can continue for up to several hours after an exercise session ends.
Strength Training Effects
During a typical weightlifting workout, you only burn off roughly 180 to 266 calories in an hour, according to Harvard Medical School. However, weightlifting, calisthenics and other strength-training exercises also gradually increase the size of your muscles. Each pound of muscle tissue on your body burns through about 35 to 38 calories every day, and this burning process is not limited to the hours following your exercise session. As the size of your muscles increases, your body burns through even more of your calorie reserves every day to meet your ongoing energy needs.
Combined Exercise Programs
To burn calories and control your weight, the Centers for Disease Control and Prevention recommends that you engage in both aerobic exercise and strength training. Minimally, you need to get about 150 minutes of weekly aerobic activity and two days per week of weightlifting or another strength-training exercise such as calisthenics or resistance-band training. If you're new to exercising or haven't exercised for a long time, talk to your doctor before you begin a new fitness routine. Typically, you will start out with smaller amounts of exercise and increase your efforts gradually.
If you're a new exerciser, you will typically not be able to exercise at an intensity that promotes prolonged calorie burning after an aerobic workout, SpineUniverse notes. If you start a strength-training program, you will usually start to increase the size and strength of your muscles in a matter of several weeks. You can get some benefit from aerobic activities even if you can only exercise for 10 minutes at a time. You can get the benefit of strength-training exercises in workout sessions that last only 20 or 30 minutes.
- Centers for Disease Control and Prevention: How Much Physical Activity do Adults Need?
- Harvard Health Publications: Calories Burned in 30 Minutes for People of Three Different Weights
- SpineUniverse; Add Muscle to Your Game...And Your Life; Ellington Darden, Ph.D.
- American College of Sports Medicine: ACSM Issues New Recommendations on Quantity and Quality of Exercise