Approximately one American turns 65 years old every 8 seconds, and this trend is projected to continue until the year 2029 (7). The American College of Sports Medicine (ACSM) defines an older adult as any individual older than 65 years or any individual between the ages of 50 and 64 years with clinically significant conditions or physical limitations that influence movement, physical fitness, or physical activity (19). This definition accurately reflects the heterogeneity within the older population. Chronological age, the passage of time in years since birth, is a poor indicator of an individual’s true health status (9). Biological or physiological aging reflects changes in structures and functioning of the human body that affect an individual’s ability to survive or an individual’s appearance (9).
Aging, the loss of functional reserve capacity, is a universal process that occurs in everyone, whereas disease is a selective process and not considered part of the aging process. Aging and disease are coupled with more than 50% of all older adults having at least one chronic condition (7), such as hypertension, atherosclerotic cardiovascular disease, cancers, chronic obstructive pulmonary disease, type 2 diabetes mellitus, osteoarthritis, and osteoporosis (2). Frailty is an age-associated physiological syndrome that results from the reduction in functional reserve capacity of multiple organ systems (6,13). Death, institutionalization, disability, high morbidity, acute illness, and increased health care use highlight the vulnerability of frail older adults (13).
Exercise has been shown to prevent and/or remediate the inevitable loss of functional reserve capacity, the increased probability of comorbidity and disability, and the potential of becoming frail as one ages. This column presents exercise testing and training strategies specific for both healthy aging and the frail older adult.
SPECIAL CONSIDERATIONS FOR EXERCISE TESTING OF HEALTHY AND FRAIL OLDER ADULTS
Baseline performance measures of strength, cardiovascular health, flexibility, and balance (neuromuscular coordination) are important and a prerequisite for the development of an individualized exercise program in healthy and frail older adults. Before baseline testing or physical activity, healthy and frail older adults should undergo a preparticipation health screening consistent with ACSM guidelines (1).
Cardiovascular exercise testing in healthy and frail older adults should include careful selection of the mode of exercise to account for any gait disturbances or instability. Initial exercise intensity should be low and progressive protocols that incorporate minimal increases in work rate between stages (11). Walk tests of varying duration (6 or 12 minutes) offer a suitable replacement to treadmill or cycle ergometer-based protocols (3).
For strength testing, peak skeletal muscle strength can be determined using a maximum (1-RM). Skeletal muscle endurance can be measured with lightweight dumbbells or weight machines. Skeletal muscle power requires the use of specialized pneumatic devices or dynamometers that can control the speed of contraction. If available, these two devices are extremely well suited and safe for testing healthy and frail older adults (11).
Flexibility and balance assessment should be incorporated into any preexercise training testing. Range of motion (ROM) is an important component in the performance of many activities of daily living and can be assessed on large joints with an inexpensive goniometer (11). The assessment of balance or neuromuscular coordination is of paramount importance in healthy older adults at risk of falling and especially frail older adults. Simple single-limb stands, tandem walking, or using an age and health status performance test such as the Short Physical Performance Battery (timed standing, gait speed, and chair rises) provides valuable information on lower-extremity function and neuromuscular coordination (10).
EXERCISE PROGRAMMING FOR HEALTHY AND FRAIL OLDER ADULTS
Healthy older adults acquire considerable health benefits from participating in regular exercise, and these advantages will continue to occur throughout their lives. Exercise programming recommendations for older adults have been established (Table) (16). Frail older adults present unique challenges when developing exercise programming because their conditions and functional abilities can be quite diverse. Exercise programming recommendations for frail older adults are not common. However, exercise has been shown to increase gait speed and improve balance and performance in activities of daily living (8). In 2014, Cadore and colleagues provided a comprehensive review of the scientific literature investigating exercise training and prescription in frail older adults and generated recommendations for exercise programs for frail older adults (Table) (5).
SPECIAL TRAINING CONSIDERATIONS FOR HEALTHY AND FRAIL OLDER ADULTS
Exercise programming in healthy older adults can be relatively straightforward and use many of the same principles and techniques as those used in younger adults. However, this is the exception and not the rule because the majority of older adults partake in a sedentary lifestyle. Furthermore, the majority of older adults present with at least one chronic condition (7). Therefore, special care is needed when monitoring older adults as they progress through an exercise program.
The ACSM/AHA recommendations emphasize that any exercise program should involve a gradual stepwise progression with the intention to increase physical activity across a period (16). Aerobic exercise may prove difficult for older adults, especially frail older adults, because of their limited neuromuscular capacity and ambulatory limitations (6). The practitioner should pay particular attention to the mode of aerobic exercise. The mode will be dictated by the participant’s current health and fitness state. Neuromuscular and functional performance assessments can be extremely beneficial to determine if weight-supported aerobic exercises are needed by an individual. Weight-assisted activities such as recumbent cycling or stepping and water-based activities can be used by those who are suffering from joint pain or ambulatory deficiencies. Aerobic exercise in frail older adults should incorporate activities such as walking, with emphasis placed on changes in pace, directional transitions (12,15), treadmill walking (20), step-ups, stair climbing, and stationary cycling (6,20).
Attention should be paid to the intensity and duration of aerobic exercise in the beginning as deconditioned, ambulatory challenged, frail, and diseased participants may struggle to exercise at the recommended intensity and duration. Exercise intensity should not be the focus with both older adults and frail elderly, and the practitioner should allow the participant’s health status and fitness level to dictate the level of exertion. Exercise tolerance is highly variable within both of these populations and, therefore, the duration of aerobic exercise also is highly variable. Small bouts of exercise performed below recommended levels throughout the day may characterize a more participant-friendly approach (12). In the first few weeks of training, the participant may only be able to perform exercise for 5 to 10 minutes, and progression should be gradual (6). Monitoring of the heart rate and perceived level of exertion throughout the exercise session and the postexercise blood pressure can provide valuable feedback and assist in personalizing an individual’s progression (3).
Healthy and frail older adults retain the ability to increase their skeletal muscle strength and power, to enhance their neuromuscular properties, and to increase their muscle mass through strength training, including progressive weight training, elastic bands, or weight-bearing calisthenics (10,14,18). Resistance exercise is highly modifiable and can be tolerated by most individuals. For those individuals who are new to resistance training or are too weak initially, the practitioner can use body weight, plastic tubing or bands, or household items as resistance to increase an individual’s initial strength. Proper technique is critical in the early stages of any resistance activity and should be observed closely and immediately changed if needed to attenuate the potential for injury (11). Proper technique includes educating the individual regarding the Valsalva maneuver (breath holding for an extended period) while performing resistance exercise (11).
Skeletal muscle power is an important predictor of functional limitations in older adults. The age-related loss of muscle power occurs earlier and more quickly than muscle strength (2). Bean et al. (4) demonstrated that older adults with reduced muscle power production were at greater risk of mobility impairments (two- to three-fold) compared with older adults with depleted muscle strength. Therefore, the inclusion of higher-velocity resistance training, especially lower-limb resistance training, should be incorporated into any strength training program. Cadore and associates (5) and Reid and Fielding (17) demonstrated the importance of including power training in the exercise programming of frail older adults. Their results demonstrated a significant improvement in muscle power output, strength, and functional performance measures (5,17). Furthermore, Reid and Fielding (17) demonstrated that high-velocity resistance training directed at enhancing lower-limb muscle power has been well tolerated, safe, and successful among individuals older than 80 years.
Finally, flexibility and balance are necessary components of any exercise program and should not be overlooked. Both are crucial to the successful performance of not only activities of daily living but also instrumental activities of daily living. Flexibility exercises should be static and not ballistic (3). Furthermore, the stretch should not produce pain and, as ROM increases, the participant should be encouraged to increase the stretch to a comfortable level (11). Balance training (neuromuscular coordination) is of paramount importance within both populations and should be included regardless of health status. Incorporation of semitandem, tandem, single-leg stance, or any activity that progressively reduces the base of support provides an excellent challenge (12). If the previously mentioned activities fail to provide a sufficient challenge, these tasks can be performed with eyes closed to decrease sensory input. With the increased risk of falls associated with aging and the ambulatory challenges faced by both community-dwelling and frail older adults, it is very important that any exercise program incorporates activities that challenge the participant’s neuromuscular coordination.
The next column will address a very important public health issue, that of exercise testing and training strategies for children with obesity.
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© 2015 American College of Sports Medicine.
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