Aerobic fitness is the biochemical, cardio-pulmonary, and muscular capacity to generate useful energy for physical activity. It is a relative matter, in part determined by age, sex, heredity, disease, and circumstance. An 80 year old woman might be at her maximum aerobic fitness level providing the capability to do daily chores, work in the garden for short spells throughout the day, take the dog for a walk to the neighbors, and climb a few flights of stairs per day. An elite distance runner might be optimally fit when he runs a marathon in just over two hours after months of training at levels of 100 miles of running per week.
In holistic health terms aerobic fitness is related to a level of functioning that provides the highest level of benefits with the smallest amount of disadvantages consistent with a well-balanced lifestyle and supporting the individual's life goals. That's different from maximal aerobic capacity or endurance.
30-60% of Canadians and Americans engage in no leisure-time physical activity.
The Health Benefits of Aerobic Exercise
So how should we use aerobic exercise to improve our entire well-being and not just fight stress? Looking at how the body adapts to physical activity, and the documented health benefits it receives, will help us answer this question. A reasonable amount, frequency, duration, and intensity of aerobic exercise has been documented to do the following:
It increases physical energy. This means more energy to accomplish what we need or want to do on a daily basis. Heart and lung capacity and efficiency increase. The oxygen carrying capacity of the blood improves. There is a more efficient use of various energy pathways in the cells and tissues of the body, the muscles especially.
There is an improvement in mental health with exercise. Depression, anxiety, tension are all reduced. Intellectual functions and learning are enhanced. Multiple causes for these improvements have been researched and can be explained, in part, by increased blood flow to the brain, hormonal changes, alterations in neuro-transmitters, the production of endogenous opiates (mood elevators within the brain), reduced stress from balancing of the nervous system's autonomic functions, and the tranquilizing effects of increased body temperature. This does not even take into account the psychological benefits of achieving goals, discovering a sense of self control, improving self esteem, transforming one's self image, or socializing with others.
Longevity is increased. This is due in part to physiological improvements such as a decrease in blood pressure in those millions with hypertension, increases in blood vessel strength and size, decrease in body fat, decrease in blood cholesterol, an increase in heat acclimatization, more rapid recovery from illness, and delay of the aging process.
Other health benefits: lowering the risk of injury by strengthening the bones, ligaments, tendons, and muscles; improvements in work performance; regularity of bowel movements, thus reducing conditions like toxic bowel syndrome, constipation, and hemorrhoids; improvements in liver and kidney function resulting in enhanced detoxification of the body's metabolites and poisons; better digestion, thus improvements in nutritional health; better menstrual function due to regulation of hormones and increased blood circulation; healthy child bearing; improvements in sleep patterns; reductions in skin infections; and less hunger.
10% of Americans and 25% of Canadians are regularly and vigorously active.
So how do we achieve these benefits? How do we determine the correct level and type of aerobic training? As usual the first step is to assess the present level of fitness and then determine how much improvement is needed. Once again, there are multiple levels of fitness testing. On the lower end of the scale are submaximal aerobic exercise tests which measure one's ability to complete an aerobic task, like run a mile or run for about fifteen minutes in reasonable comfort.
A more precise calculation of this physiological limit can be made through maximal treadmill or cycle ergometer exercise. Monitoring of ventilatory capacity of the lungs at the same time with an evaluation of blood gases, blood pressure, heart rate, ECG readings can all add more information. For most purposes it is unnecessary. There are also some risks in doing maximal testing on the old and the infirmed. These more precise tests can be performed on the serious athlete if desired, or on people needing special care, as those with high blood pressure, cardiovascular disease, and in rehabilitation programs.
For the most part the submaximal fitness testing readily available at YMCA exercise programs or health club, is adequate for most peoples' health enhancement needs. If you are over forty and/or not accustomed to regular aerobic exercise, it is advised that you first consult with a health care professional specializing in sports medicine for a preliminary evaluation. This can be a chiropractor, physical therapist, exercise physiologist, naturopath, osteopath or medical doctor. Contacting the American College of Sports Medicine for a referral to someone appropriate in your locale is a good approach.
It is important to know our target heart rate regardless of what fitness activity we choose. This is the heart beats per minute that, if sustained during aerobic exercise, will give the best conditioning. Conditioning increases in proportion to intensity, duration, and frequency of exercise within this training zone with diminishing returns at the maximal limits. Fitness improvement generally occurs when the heart is beating at 60-90% of its maximum capacity (The elderly can elicit an improvement from training with as little as 40% of maximal heart rate.). To calculate maximum heart rate just subtract your age from 220. (There are more accurate measures for athletes with low resting heart rates.) Adults with no symptoms of disease can achieve their best conditioning at 70-85% of this figure. Patients on a cardiac recovery program generally start at 50-65% of maximal heart rate for their training zone. Elite athletes have to push the upper limits of this zone to see improvement. Pushing these upper limits in not only intensity but duration and frequency can result in diminished health from over training. The immune system can be depressed and energy reserves sapped. Fatigue and sickness often result. If we can get 30 minutes of aerobic conditioning 3-5 times per week it will help greatly in giving us a greater capacity to respond to daily stress.
Below is a list of the most effective and safe aerobic activities. The safest activities are at the top of the list.
- cross-country skiing and quality indoor x-country ski machines such as Nordi-Trac
- bicycling, including stationary bikes
- non-impact aerobics
- water aerobics
- stair climbing, including stair climbing machines
- power walking with hand held weights or ski poles
- aerobic circuit training with weight training equipment
- aerobic backpacking and hiking
- handball, racquetball, squash
- aerobic sculling, paddling or rowing
- rowing machines, including Health Rider types
- tantric sex (just checking to see if you're still awake)
One of the best sites for guiding you through a thorough fitness program: Shape Up.org/
Make sure you are getting the aerobic exercise you need for best health.