Aerobic Fitness

Regular physical activity is protective to the health in numerous ways as shown in the list below. To experience these health benefits it's necessary to meet certain criteria. The following guidelines¹ can help you design your personal activity program to be both effective and safe.

Physical Activity

• Burns excess calories to achieve and maintain a healthy weight
• Lowers the blood pressure and improves blood cholesterol levels (HDLs) reducing the risk of heart attack and stroke
• Improves insulin sensitivity helping prevent or control diabetes
• Improves mood, self image, and helps combat depression and anxiety
• Strengthens muscles and bones which decreases injury risk and helps prevent osteoporosis
• Reduces the risk for colon cancer, breast cancer, and certain other cancers
• Reduces your overall risk of mortality from any cause, by 10% or more²

        Source: U.S. Surgeon General's Report, Physical Activity and Health

Choice of Activities

The good news for most people is that physical activity doesn't need to be strenuous to be beneficial. When first starting, choose moderate activities you enjoy and that are within your current level of capacity. As you get used to regular activity and want a greater challenge you can participate in more vigorous activities.

National fitness guidelines state:

"Every adult should accumulate 30-60 minutes of moderate-intensity physical activity on most, preferably all, days of the week."

American College of Sports Medicine, CDC, Institute of Medicine, 2002

Moderate Physical Activities

The following moderate activities are similar in energy expenditure and are good examples of a daily fitness program designed to improve cardiovascular health. Walking is a good activity that is safe for most people and requires no additional skill. You can also benefit from:

• Gardening for 30-45 min
• Walking for 35 minutes (1.75 to 2 miles)
• Bicycling, 8-10 mph for 30 minutes
• Active dancing for 30-40 minutes
• Mowing the lawn with a push, power mower, raking leaves, or active gardening for 30-40 minutes
• Water aerobics for 30-40 minutes
• Swimming laps at a moderate pace for 25-30 min
• Conditioning exercises, 30 to 40 min.
• Golfing for 45 to 60 minutes
• Playing table tennis for 45 to 60 minutes
• Playing volleyball, moderately, for 45 to 60 minutes

Safety

When beginning an activity, ease into it. Give the heart and muscles time to warm up for more vigorous activity to follow. The same is true for the end of the activity. Cool down gradually with easy walking, stretching, or other lower intensity activity.

Most healthy people don't need to see their doctors before starting a moderate-intensity activity program. However, if you have a health problem such as diabetes, obesity, or a heart problem, get your doctor's guidance before beginning a fitness program.

Duration

How long do I need to exercise? Notice that the guidelines say to "accumulate 30+ minutes daily". You don't have to get all your exercise at one time. It may be easier for you to break it up into two 15 minute sessions or even three 10 minute sessions.

For example, if you walk 15 minutes to catch a bus in the morning and again in the evening, you would get your 30 minutes. Or maybe you walk 15 minutes at noon each day and then bike or mow your lawn for another 15+ minutes in the evening. If you want more benefit, go a little longer. For best health, the Institute of Medicine³ recently recommended up to an hour of moderate activity daily, especially if you need help in maintaining a healthy weight.

Progression

Another safety consideration is to start easy and progress gradually. You may only be able to go 5 or 15 minutes when first starting. Gradually work up (over several weeks) to the full 30 minutes. When you can easily complete 30 to 60 minutes of activity then you can gradually increase intensity if you wish to develop higher fitness levels. It may have taken you years to get out of shape. Don't try to get back into shape overnight. Give the body time to adapt and strengthen.

Intensity

When first beginning, exercise at an easy level - one that you can maintain for 10 to 30 minutes without undue strain or fatigue. A moderate-intensity activity should feel "fairly easy to somewhat hard" and make you breathe deeply but not be out of breath. Working up a moderate sweat is also a good indication of of cardiovascular benefit.

If you are already fit and enjoy more vigorous activity, that's great. Running, skiing, tennis, and other active sports add enjoyment and challenge to a fitness program. If you have any health problems, however, or are over 40 and not used to vigorous activity, it is important to get your doctor's guidance before significantly increasing your level of physical activity.

 Keeping Motivated

Maintaining an active lifestyle for a lifetime is the challenge. Currently, about one-fourth of the U.S. adult population have no activity program (27.6%). Another half (46.2%) get some activity but not enough to become fit. Only one-fourth (26.2%) have a regular physical activity program. Even adolescents are very sedentary today. The latest surveys show that only about one-third are getting adequate physical activity for good health.² Here are some ideas to consider when planning for lifelong fitness:

• Set weekly goals and then track your progress. A goal might be 30+ minutes of activity 5 days per week. Or, it may be walking 2 miles 4 days each week. Be specific and write it down. Then check yours progress weekly.
• Exercise with your spouse or a friend. Adding a social element helps keep it fun and improves long-term success.
• Try a variety of activities. Walk, bike, swim, hike on the weekends, play tennis, garden.
• Don't overdo! If you get too tired or get sore muscles it isn't much fun anymore and many people quit. Take it easy, be consistent, and the body will adapt.
• Think of exercise as "play time." Have fun!
• Reward yourself as you reach your personal fitness goal.
• Join a fitness center, a community aerobics class, the YMCA, or a biking or hiking club.

For every hour you exercise you increase your
life expectancy by 2 hours.

Ralph Paffenbarger, Harvard Alumni Study

References
1. American College of Sport's Medicine, Guidelines for exercise testing and prescription, 6th Edition, Lippincott Williams and Wilkins, New York, 2000
2. Paul A. Estabrooks, PhD, et al. Physical activity promotion through primary care, Journal of the American Medical Association 289:2913-16, Jun 11, 2003
3. Institute of Medicine of the National Academies, Dietary reference Intakes for energy, carbohydrates, fiber, fat, fatty acids, cholesterol, protein, and amino acids. Washington DC, National Academy Press, 2002

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Health content in this article is general health information from evidence based research for healthy populations. Its purpose is not to treat disease or take the place of advice by your doctor but to promote healthy lifestyles. Persons with health problems should contact their physician for specific guidance.  Written by Don Hall, DrPH, CHES. Updated June 12, 2003 DRH, LA.