Submitted by: Jon YeanSub Lim, CSCS, USSA Doctoral Student
Introduction
Today, the average of life expectancy has gone up in the United States (U.S.) and is expected to increase even more in the future. The U.S. Bureau of Census (1994) predicted there will be more than 40 million people over 65 years old in the year 2010. The growth in the senior population of the U.S. is a similar trend throughout the world. Consequently, the health, fitness and well-being of the senior population are of increasing concern in today’s society.
Aging is a normal biological process in human beings involving the gradual alteration of body structure, function, and tolerance to environmental stress. From approximately age 30, effectiveness of various physiological functions begins a subtle decline that becomes more obvious around age 55-60. However, physiological aging does not occur at the same rate throughout the population. At the present, it is difficult to distinguish reasons of decline in physiological functions. The reasons could be from advancing age, deconditioning from physical inactivity, disease, or any combination of them (ACSM, 1995).
There is a biological and a chronological age. Biological age focuses on senescent changes in biological and physiological processes, whereas chronological age focuses on elements of calendar time. An individual who is 70 years of age may have a biological age of 45, based on his/her health and fitness status. Biological age may be reduced by regularly participating in a well-designed physical fitness program. Nakurma, et al. (1989) found that active elderly men who followed a regular exercise program were able to significantly lower their biological age with improvement in functional capacity and maximal aerobic power. This may explain that normal aging processes account only for a portion of the loss of physiological function; physical inactivity accounts for greatest amount of the loss with age (Poehlman et al., 1991). This loss from physical inactivity is avoidable through adequate and regular exercise.
The benefits of physical activity for older individuals are well documented. It improves cardiorespiratory function, reduces risk factors for coronary artery disease, and most importantly enhances of the ability to perform daily activities (Blair, 1993; Huhn, 1993). There is no clear evidence that exercise will improve longevity, but there is little doubt that it improves the quality of life in old age. It maintains endurance, strength, and joint mobility while it reduces the incidence and severity of hypertension, osteoporosis, obesity, and diabetes mellitus. The purpose of this paper is to provide general guidelines of effective and safe exercise testing and prescription for the senior adult population. The physiological changes accompanying advancing age which influence exercise should be considered in the design of effective and safe exercise programs for the senior population.
Physiological Changes With Aging
The study of physiological changes with aging come from data collected from different cross-sectional and longitudinal studies (Table 1). It is crucial to have knowledge of the physiological changes of aging in order to have a safe and effective exercise program for older individuals. With advancing age, there are gradual decreases in basal metabolic rate (BMR), bone density, maximum oxygen consumption (VO2 max), muscle mass, muscle strength, and range of motion (ROM).
Table 1
Effects of Exercise Training and Aging |
| Variables |
Aging |
Exercise Training |
| Resting heart rate |
Little or no change |
Decreases |
| Maximal cardiac output |
Decreases |
Increases |
| Resting & exercise blood pressure |
Increases |
Decreases |
| Maximal oxygen uptake |
Decreases |
Increases |
| HDL |
Decreases |
Increases |
| Reaction time |
Decreases |
Increases |
| Muscular strength |
Decreases |
Increases |
| Muscle endurance |
Decreases |
Increases |
| Bone mass |
Decreases |
Increases |
| Flexibility |
Decreases |
Increases |
| Fat-free body mass |
Decreases |
Increases |
| Precent body fat |
Increases |
Decreases |
| Clucose tolerance |
Decreases |
Increases |
| Recover time |
Increases |
Decreases |
| (ACMS Guidelines for Exercising and Prescription, 1995) |
The benefits associated with exercise are well documented showing the enhancement of the ability to perform daily activities in old age (Table 1). Most of the physiological changes of aging can be improved with regular exercise training.
Exercise Testing
The American College of Sports Medicine (ACSM) recommends that older individuals should obtain a medical clearance from their physician prior to maximal exercise testing and before their participation in vigorous exercise. In addition, health screening of the participant should be conducted in order to optimize safety during exercise testing and participation to develop an individualized, safe and effective exercise prescription.
After the completed health screening, the participant should have a pre-exercise evaluation which will provide a baseline measure of body composition, cardiovascular endurance, flexibility, and muscle strength. The protocols for testing older individuals need to be modified for any special needs they may have. The ACSM provided factors to be considered when selecting an exercise testing protocol for older individuals (Table 2).
Table 2
Factors to Be Considered When Selecting an Exercise Testing Protocal for Older Adults |
| Characteristic |
• |
Suggested Test Modification |
| Low VO2 max |
• |
Start at low intensity (2-3 METs) |
| More time to attain a steady state |
• |
Long warm-up (>3 min), small increments in work rate (0.5-1.0 MET per stage), longer stages |
| Increase fatigability |
• |
Reduce total test time (ideally 8-12) |
| Increase need to monitor ECG, blood pressure, and heart rate |
• |
Cycle ergometer preferred |
| Poor balance |
• |
Cycle ergometer preferred |
| Poor ambulatory ability |
• |
Increase treadmill grade rather than speed |
| Poor neuromuscular coordination |
• |
Increase amount of practice, may require more than one test |
| (ACSM Guidelines for Exercise Testing and Prescription, 1995, p.230) |
These baseline measures are very useful in the development of exercise prescription and educating participants in physical fitness and their individual status.
Exercise Prescription
The American College of Sports Medicine (1991) recommends the goals for exercise in the senior population should be to maintain functional capacity for independent living, reduce risk factors for heart disease, retard the progression of chronic disease, promote psychological well-being, and provide opportunities for social interaction.
Although many of the general principles of exercise prescription are the same for individuals of all ages, special care must be given when setting up a fitness program for older individuals. Exercise programs for older individuals should be tailored to combine endurance, muscle strength, and flexibility to promote the quality of their life. The general exercise prescription guidelines for the senior population are developed from the ACSM guidelines (1995).
Mode
The mode of exercise for the older population should be activities with low-impact on their joints. The activities include walking, stationary cycling, water exercise, swimming, or machine-based stair climbing. The activity needs to be accessible, convenient, and enjoyable to the participant.
Duration
The duration of an exercise program should start with short periods and gradually progress in length. During the initial stage, it may be difficult for some old adults with physiologic limitations to perform exercise for 20 minutes. It will be possible for them to perform exercise in shorter sessions of five to 10 minutes repeated several times throughout the day. In addition to the duration of the exercise program itself, elderly people need additional warm-up and cool down time, perhaps as much as 10 minutes or more.
Intensity
The intensity of the exercise program must start out low since elderly people are more prone to exercise-related injuries. Because low intensity exercise is associated with a lower risk for injury, it should be encouraged in the elderly population. Exercise intensity should be sufficient to overload the cardiovascular, pulmonary, and musculoskeletal systems without overstraining them. The recommended intensity by the ACSM for older adults is 50 to 70% of heart rate reserve (1995). The intensity level of exercise should be regularly monitored by heart rate, or rating of perceived exertion (Borg, 1982).
Frequency
Generally, the frequency of exercise programs recommended is three to five days per week (ACSM, 1995). Emphasis on more frequent activity (five to seven days per week) may be made with seniors if they exercise very low intensity with short duration. This recommended increase in frequency has physiological relevance for the maintenance of endurance capacity as well as flexibility. In addition, the greater frequency may enhance compliance and lead to a greater probability of the subject assimilating physical activity in the daily routine.
Progression
Progression should be conservative and gradual for older individuals. The initial stage, usually four to six weeks, should include low intensity exercise to permit adaptation with minimal risk for injury. Elderly subjects may need a longer period of adjustment before exercising at higher intensity levels. It is better to increase exercise duration initially rather than intensity in order to avoid injury and ensure safety. Progression in an exercise program should be based on how well the individual is responding to the current regimen, the medical and health limitations of the individual, and individual goals. Exercise programs should be reviewed on a regular basis to ensure they are meeting the needs of the participant.
References
American College of Sports Medicine. (1991). Guidelines for Exercise Testing and Prescription (4th ed). Baltimore: Williams & Wilkins.
American College of Sports Medicine. (1995). Guidelines for Exercise Testing and Prescription (5th ed). Baltimore: Williams & Wilkins.
Blair, S. (1993). Physical activity, physical fitness, and health. Res Quart Exerc Sport 64: 365-376.
Borg, G. (1982). Psychophysical bases of perceived exertion. Medicine & Science in Sports & Exercise, 14, 377-381.
Hyhn, R. (1993). Cardiac rehabilitation in the cost containment environment. Cardiopul Phs Ther J 4: 4-8.
Nakamura E., Moritani T., & Kanetake, A. (1989). Biological age versus physical fitness age, Eur J Appl Physiol 58: 778-785.
Poehlman, E., McAuliffe, T., Van Houten, D., & Danforth, E. (1991). Influence of age and endurance training on metabolic rate and hormones in healthy men, Am J Physiol 159: 66-72.
U.S. Bureau of Census. (1994). Statistical Abstract of United States
