Fewer than 30 percent of Americans exercise enough to reap the many health benefits of aerobic exercise. These benefits include reductions in cholesterol levels, blood pressure and body fat, a decrease in your risk of developing heart disease and diabetes, as well as an increase in bone and muscle strength, metabolic efficiency and your ability to deal with stress. Certified fitness instructor Kathleen Ekdahl states that for aerobic exercise to be effective, you should plan on at least 45 minutes of aerobic activity each time you exercise.
Aerobics Defined
Aerobics are exercises that the American Academy of Orthopaedic Surgeons describes as vigorous, repetitive movements of large muscle groups. You reap the health benefits of aerobic exercise when you perform them long enough to force your heart to speed up and your lungs to work harder. The goal of your aerobic workout is to achieve 60 to 80 percent of the maximum heart rate for your age. While you can get this information from a chart at your gym or doctor's office, you can also calculate it yourself by first subtracting your age from the number 220 and then finding the percentage. For example, if you are 40, subtract that number from 220 to get your maximum heart rate: 220 - 40 = 180. Your target heart rate will be 108 to 144 beats per minute. When you stop exercising, check your pulse, count beats for 15 seconds, and then multiply the number you get by 4 to determine your current heart rate.
Why 45 Minutes
A 20- to 30-minute workout is technically long enough to achieve the benefits of aerobic exercise. However, a 45-minute aerobic workout is more appropriate if you do not work out every day, or if you also want to lose weight. To illustrate the difference that 15 minutes can make in the calories you burn, 30 minutes of aerobic dance burns about 342 calories while 45 minutes burns 513 calories. Bicycling at 12 mph for 30 minutes burns 283 calories. For 45 minutes, it burns 425 calories. Water aerobics burns 140 calories in 30 minutes vs. 210 calories in 45 minutes. Keep in mind that a 45-minute aerobic workout is a goal to strive for, not a point at which you start. Ekdahl suggests you start with 20 minutes and gradually work up to 45-minute sessions as your heart, lungs and body become stronger.
Exercise Intensity
When you plan a 45-minute aerobic workout, make sure to choose exercises appropriate for this time frame. ShapeFit.com recommends that a 45-minute cardio workout be slow and steady, with an emphasis on low-intensity exercises. Performing high-intensity exercises leads to burning short-term energy rather than fat and may place too much stress on your joints.
Examples
Examples of low-intensity aerobic exercise include walking, either outside or on a treadmill, biking outside or on a stationary bike, using an elliptical machine or stair stepper, or participating in water aerobics.
References
- The New England Wellness Web: Understanding the Benefits of Aerobic Exercise
- American Academy of Orthopaedic Surgeons: Aerobic Exercise
- Family Education: Aerobic/Cardio Exercise
- Dummies: Following a Cardio Plan for Weight Loss
- ShapeFit: Cardio Exercises to Burn Major Calories
- Spine-Health: Low-Impact Aerobic Exercise
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