Filed under: Aerobic exercise
Reports estimate that one of every four deaths is attributed to heart disease. Cardiorespiratory (aerobic) activities such as jogging, cycling, and swimming directly improve the function of the heart, which decreases the risk of coronary artery disease, high cholesterol, high blood pressure, stroke, and type II diabetes. Aerobic fitness is important enough that all active-duty service members must complete an aerobic fitness assessment, such as a maximal effort timed run, as part of their annual physical fitness test.
To delve a little deeper about the changes your heart, lungs, and blood vessels undergo when you improve your aerobic fitness, read on. One important change that occurs is that your heart’s “stroke volume”—the amount of blood the heart pumps out with each beat—increases. This comes from an increase in your heart’s strength and ability to hold a greater amount of blood. This in turn reduces your heart rate (HR) both at rest and at all levels of exercise. In fact, with consistent training, your resting HR could likely decrease as much as eight to10 beats per minute. That’s about 5 million fewer heartbeats in a year! Simply put, aerobic training means your heart has to do less work to get your job done.
Changes also occur to your blood and blood vessels with aerobic fitness. Your blood vessels increase in diameter and are better able to expand and constrict. This allows blood to move through your blood vessels with less resistance, reducing your blood pressure. And what happens to your blood? The levels of plasma (the liquid portion of the blood), red blood cells, and hemoglobin all increase, which means that your blood can carry more oxygen.
Altogether, the physiological changes mentioned here should make it easy to see why aerobic exercise is so important. If you want to learn more about how to get started improving your cardiorespiratory health through exercise, visit these Performance Strategies from HPRC.
Deployments, injuries, transitions—just a few of the many things that can interfere with your normal exercise routine. Too long a break and your cardiovascular—or aerobic—fitness may suffer. For optimal performance, however, getting your heart and lungs back in action is critical. If you’ve been away from your routine for a while, start slowly and gradually increase intensity and duration. Be patient and stick with a routine, even on days you don’t feel like it. Mix up your routine when you’re able with different types of aerobic exercise such as biking, running, swimming, and rowing. For help planning your comeback, check out HPRC’s Performance Strategies for Rebuilding Cardiovascular Fitness. If you’d like to learn more about aerobic conditioning specifically for the PRT/PFT, read part 1of our training series.
In a recent study investigating risk factors for discharge from Army Basic Combat Training (BCT), researchers concluded that increased risk for both men and women was associated with failure on the initial two-mile run test. The current Physical Fitness Tests (PFT) or Physical Readiness Test (PRT) use a one and a half to two-mile run test to assess cardiovascular, or aerobic, fitness.
When mapping out a fitness program, learn the components of the FITT principle and apply them for each type of training. FITT stands for “frequency,” or how often; “intensity,” or how hard; “type,” or the kind of activity; and “time,” or how long. Progression (see below) is also an important part of an exercise plan. Using the FITT Principle, here are some guidelines to help optimize your cardiovascular fitness.
Frequency. The U.S. Surgeon General and other U.S. government agencies recommend physical activity on three or more days a week.
Intensity. According to updated guidelines The American College of Sports Medicine (ACSM) recommends adults engage in moderate-intensity exercise (i.e., at 40-60% Heart Rate Reserve (HRR)) five days a week or vigorous-intensity exercise training (i.e., at ≥ 60% HRR) three or more days a week. They also recommend a combination of moderate- and vigorous-intensity exercise. You can use this calculator from Kirtland AFB to determine your HRR.
Type. ACSM defines aerobic activities as being continuous, rhythmic, and using large muscle groups, such as your lower and upper body muscles. Examples of these kinds of activities are running, biking, swimming, rowing, and jump roping.
Time. The Surgeon General, ACSM, and American Heart Association recommend expending at least 1,000 calories per week through exercise (i.e., in addition to calories burned through normal everyday activities). This can be achieved through moderate-intensity exercise, as described above, and should last about ≥ 30 minutes per day for a total of ≥ 150 minutes per week; or with vigorous-intensity exercise for ≥20 minutes per day for a total of ≥75 minutes per week. The maximum safe duration is unknown, but exercise lasting more than an hour and a half increases risk of overtraining and/or overuse injuries such as stress fractures.
Progression. During the initial phase of an exercise program, ACSM recommends increasing duration (minutes per session) gradually. Increasing 5-10 minutes every one or two weeks over the first four to six weeks of an exercise program is reasonable for healthy adults. After an exercise routine has been maintained for one month or longer, it is reasonable to gradually increase frequency, intensity, and/or time over the next four to eight months. As a general rule of thumb, though not scientifically backed, increasing your workloads or volume by 10% will also help you gradually progress your exercise program.
Due to the repetitive and rhythmic nature of aerobic exercise, overuse injuries can occur as a result of your training. Cross training—training with a variety of aerobic exercises—is recommended. Examples of this would be alternating running, swimming, and rowing exercise sessions.
Part two of this series (upcoming) will address the muscular strength component of PFT/PRT.
Autumn is here and so are the leaves! Rake your own leaves, or your neighbor's leaves, for a great workout. Raking is an aerobic exercise and can help strengthen your core muscles. For tips on how to safely rake leaves, read this article by Medicine.net.
The Globe and Mail (Toronto) has an interesting piece on which activity is better for you - swimming or running? The conclusion, according to the article, is that swimming is good for muscles, joints and some (but not all) cardiovascular risk factors. But to get the full benefits from aerobic activity, include some land-based exercise in your routine at least once or twice a week.