In Part 1 of this series, Tammy explained the recently updated physical activity guidelines for older adults, specifically as they relate to flexibility and stretching. In this article, she continues her review of the guidelines, as they relate to endurance and strength training.
Maximal oxygen consumption (VO2max), an index of maximal cardiovascular (CV) function, decreases five to 15 percent per decade after the age of 25. Decreases in maximal cardiac output, due to maximal heart rate decreases of six to 10 bpm per decade, contribute to the age-associated reduction in VO2max. But older adults elicit the same 10 to 30 percent increases in VO2max with prolonged endurance exercise training as young adults. As with young adults, the magnitude of the increase in VO2max in older adults is also a function of training intensity, with light intensity training eliciting minimal or no changes.
Some evidence indicates that maintaining high levels of exercise training results in a diminished rate of loss of VO2max with age in older adults. These studies generally report a reduced rate of loss expressed as a percentage of the initial VO2max value, which could be due to the athletes' initially higher VO2max. On the other hand, the rate of VO2max decline for endurance trained athletes over age 70 appears to be similar to that for sedentary adults, probably as a result of their inability to maintain the same training stimulus as when they were younger.
Because CV disease is the major cause of death in older men and women, the effect of endurance exercise training on CV disease risk factors is of vital importance. Cross sectional and intervention studies in older adults consistently indicate that endurance exercise training is associated with lower fasting and glucose-stimulated plasma insulin levels, as well as improved glucose tolerance (if initially impaired) and insulin sensitivity. Improvements in glucose and insulin metabolism are evident in older adults before changes in body weight or body composition occur.
Endurance exercise training appears to lower blood pressure to the same degree in young and older hypertensive adults. One study in older hypertensive adults reported that training at 50 percent VO2max reduced blood pressure the same or more than training at 70 percent VO2max. In a second study in older hypertensive adults, training at 40 to 50 percent VO2max decreased blood pressure, although subsequent training at 50 to 60 percent VO2max reduced blood pressure somewhat further. Thus, it appears that light to moderate intensity training is effective in lowering blood pressure in older hypertensive adults.
The minimal data available generally support the conclusion that older adults improve their plasma lipoprotein lipid profiles with exercise training. However, these changes may be secondary to training-induced reductions in body fat stores. The improvements are generally similar to those evident in young adults and include increases in HDL (the good cholesterol) levels and reductions in triglyceride levels and LDL.
Body composition is also improved with endurance exercise training in a similar fashion in older and young adults. The most consistent change is a one to four percent reduction in the overall percent of body fat with exercise training in older adults, even if body weight is maintained, and one study reported that intra-abdominal fat decreased by 25 percent in older men who lost only 2.5 kg (about 5 pounds) of body weight with exercise training. This finding is especially important for older men because intra-abdominal fat is the body fat depot that increases the most with age and is associated with other CV disease risk factors.
Maximizing both the quality and quantity of life in older adults is best accomplished by adding activities like walking, swimming and cycling into an individual's daily lifestyle.
The initiation of a regular physical activity program can produce numerous changes in the CV system and in certain CV disease risk factors that run counter to the deteriorations that manifest with aging. While the CDC/ACSM guidelines recommend light to moderate intensity lifestyle physical activities to optimize health, moderate or high intensity exercise may be required to elicit adaptations in the CV system and in CV disease risk factors. The only consistent beneficial CV response to light to moderate intensity exercise training in older adults is a reduction in blood pressure in older hypertensive adults. However, the initiation and maintenance of long term light to moderate intensity physical activity programs in older adults may reduce the rate of age-associated deterioration in numerous physiological functions, even if they do not result in absolute increases in these measures that, in the long run, should benefit both quantity and quality of life.
Aerobic exercises do not require excessive speed or strength, but they do place demands on the cardiovascular and respiratory systems. Previously, this was considered the only type of exercise that truly improved health and fitness. We now know that strength training also improves the various systems in the body and has the added benefit of preserving strength so that people can continue to perform ADLs and other activities. Remember that frailer adults might need to improve their strength before they can seriously begin to work on endurance.
The number of healthy older individuals who are active in sports has increased significantly. These individuals continue to perform at a high level, although there appears to be a loss in functional capacity that cannot be overcome by training. No accepted theory of aging exists, but older athletes may be limited primarily by the inability to maintain the same volume and intensity of training. Also, older athletes appear to respond more slowly to the same training load than do younger athletes. The principles of training in older athletes are similar to those in young athletes. However, additional days of recovery and cross training may be necessary to prevent orthopedic injuries. Older adults need to train smarter, not harder. They can't expect to continue with the same intensity of training as when they were younger, and they have to be a little more creative.
To establish and maintain a training intensity that is both safe and capable of producing physiological improvements, the intensity level of the exercise needs to be regularly monitored by rating of perceived exertion (RPE-Borg Scale) and/or by heart rate count. As a personal trainer, you should be familiar with both of these. An intensity level of 40 to 75 percent VO2 max, which translates to roughly a 12-14 on the Borg six-to-20 scale, sustained for 20 to 60 minutes is recommended for older adults.
How much work is done depends on how hard and for how long someone exercises. Older adults with chronic disease should work out at a lower intensity for a longer period of time, rather than at a high intensity for a shorter period of time. A frequency of three to five days per week is the general recommendation with the goal of an overall energy expenditure of 1000 calories per week.
Strength Training Guidelines
Once adults pass the physical prime of their teens and 20s, they annually lose an average of 10 ounces of lean body mass, which is mostly in the form of muscle tissue. Unchecked, this gradual loss of muscle strength is the main reason elderly Americans have difficulty performing the tasks of daily living, which ultimately leads to their loss of independence. This phenomenon, called sarcopenia, is derived from Greek words meaning, “vanishing flesh.” It is NOT an inevitable consequence of aging. Instead, it is an inevitable consequence of disuse.
Another important reason for older people to strength train is evidence suggests that exercise might decrease the rate of bone loss associated with osteoporosis and reduce the likelihood of falls that result in hip fractures. A frightening statistic is that almost 24 percent of people over age 50 who have hip fractures die within a year. Falling is a serious public health concern among elderly people because of its frequency, the morbidity associated with falls and the cost of the necessary healthcare. Unintentional injury, which most often results from a fall, ranks as the sixth leading cause of death among people over 65 years of age. Muscle weakness has been identified as one of the biggest potentially modifiable risk factors for falling. In the late 80s to early 90s, studies began indicating that despite a decrease in the number of muscle fibers and muscle strength, muscle function can be maintained and/or improved with training, even in the very old.
A slight increase in muscle strength at any age can improve quality of life and stave off the frailty that used to be considered a normal part of getting old. While strength training is not the only type of exercise that is important for older adults, it should be obvious that the frailer a person becomes, the greater the importance of strength training. Sometimes, strength training and flexibility are the only types of exercise in which the elderly can engage until they gain enough muscle strength to allow them to work on their endurance and balance. In his book, Specialized Strength Training: Winning Workouts for Specific Populations, Wayne Westcott, PhD, and Susan Ramsden list 13 health and fitness benefits that result from strength training by older adults. They are as follows: avoidance of muscle loss and metabolic rate reduction; increased muscle mass and metabolic rate; reduced body fat and resting blood pressure; increased bone mineral density, glucose metabolism, and gastrointestinal transit; improved blood lipid levels; and reduced low back pain, arthritic pain, and depression.
Two equally important factors facilitate the strength building process. The first is progressive resistance exercise to stress the muscles and stimulate physiological adaptation. The second is sufficient recovery time to permit tissue repair, building and protein overcompensation, leading to larger and stronger muscles. If muscles are not given enough time to rest, clients may develop overuse injuries and/or muscles may break down rather than build up. Westcott recommends that older adults allow 72 to 96 hours for recovery before exercising the same muscle group again. This is considerably different than the 48 hour guideline that is typically quoted as the industry standard.
Dr. Westcott suggests the following guidelines:
Exercises: Strength training guidelines for seniors call for one exercise for each of the main muscle groups.
Frequency: These exercises should be performed two to three times per week. Recent studies have shown two times per week to be at least as productive as three times per week.
Sets: Single and multiple set training protocols have proven effective for increasing muscle strength and mass in senior men and women, but studies comparing one and three sets of exercise have found no significant developmental differences during the first few months of training. It is suggested then that seniors begin strength training with one set of each exercise, moving onto three sets as they progress.
Resistence: The training resistance or weight load should be between 60 and 90 percent of 1RM to increase muscle size and strength.
Repetitions: The generally recommended number of repetitions per set is eight to 15. Most people can perform about eight repetitions with 80 percent of their maximum resistance and about 12 repetitions at 70 percent of their maximum. For those with limiting chronic conditions, it is advisable to begin with lighter weight loads that allow about 15 reps per set. This higher repetition protocol adds a margin of safety while providing about the same strength training stimulus. Research has shown that the number of repetitions is not important as long as muscle fatigue for each exercise set occurs within a 30 to 90 second (anaerobic) time period. When the muscle reaches fatigue within this time period, strength gains are statistically equal when using higher repetitions with lighter weight/resistance (15 reps at 60% 1RM) compared to lower repetitions with heavier weight/resistance (6 reps at 90% 1RM). This is sometimes a difficult concept for someone to accept as true if they are used to lifting heavy, but there are numerous research studies stretching from 1991 to the present that confirm this.
Progression: The key to muscle development is progressive increases in resistance. Whenever the repetition goal can be performed with proper form to muscle fatigue, raise the weight by five percent.
Speed: The general consensus is that older adults should use controlled movement speeds when performing strength exercises. Because six second repetitions have a long, successful history, this speed is recommended for older exercisers. The cadence is two seconds up (concentric phase) and four seconds down (eccentric phase).
Range: It is important for seniors to develop strength throughout their full range of motion. Full range exercise is necessary for building full range muscle strength. So seniors should perform each exercise through the complete range of joint movement, taking their muscles from their fully extended position to their fully contracted position and back. But if any part of the exercise causes pain, then the range of motion needs to be adjusted appropriately. Training range should only be through PAIN FREE range of motion.
Technique: In addition to controlled movement speed and full movement range, exercise technique is critical when training older adults. Always practice proper posture when performing strength exercises with particular emphasis on body stability and back support. To avoid unnecessary blood pressure elevation, older adults should breathe continuously throughout every repetition. They should exhale on the lift and inhale on lowering. They should never hold their breath or hold the weight in a static position since this can raise blood pressure unduly.
American Heart Associations' Views on Strength Training
In a statement issued July 17, 2007 (shortly before the new ACSM/AHA physical activity recommendations), the American Heart Association Council on Clinical Cardiology and Council on Nutrition, Physical Activity and Metabolism stressed that weight or resistance training is a complement to, not a replacement for, aerobic exercise such as walking, running, cycling or swimming. According to the Council, weight training increases the ability of people to go about their daily lives (i.e., lifting objects, taking care of themselves and their loved ones). It increases muscle mass and helps people keep their weight down. Weight training, when prescribed appropriately, can help patients after a heart attack or heart surgery.
Why it’s important: Exercise is an important part of health. However, doctors worry about the value and even safety of weight training, particularly in people who have had heart attacks or undergone heart surgery. This statement not only buttresses the value of weight training in healthy people but gives credence to the idea that, with certain precautions, weight training can be helpful to people who have had heart surgery or are recovering from a heart attack.
What’s already known: Resistance or strength training, when prescribed and supervised, can increase strength and endurance - both factors that enable people to live better, whether they have heart disease or not. Endurance training is more effective in improving stamina and the ability of the heart to pump oxygenated blood. On the other hand, resistance training, when conducted over months or years, can affect the composition and amount of muscle. Increasing muscle mass through weight training can increase your metabolism and make it easier to maintain or lose weight.
How this study was done: This review represents a consensus among experts who have reviewed published studies on weight training. While no studies were carried out by the authors, they reviewed and evaluated the most current literature and came to a consensus on the recommendations. This updated review is a revision to a review published in 2000.
What was found: Weight or resistance training, in addition to aerobic exercise, benefits people with and without prior heart disease, lowering the risk of heart ailments. Weight training should be used as a complement to aerobic exercise, not a substitute for it.
“Resistance training not only enhances the benefits of aerobic fitness, but it appears to provide the added benefit of increased functional capacity and independence. It helps people better perform tasks of daily living, like lifting sacks of groceries,” said Mark Williams, Ph.D., professor of medicine in the Division of Cardiology at Creighton University School of Medicine in Omaha, Nebraska in a released statement. The benefits of weight training include increased strength, muscle coordination, more muscle mass and higher bone density in both men and women.
The statement recommends training such as performing lifts rhythmically, doing both upper and lower body exercises and learning how to breathe effectively during exercise.
“The emphasis at the early stage of training is to allow time for the muscles to adapt and to practice good technique, thus reducing the potential for excessive muscle soreness and injury,” Williams said.
The statement suggests setting the weight limits low for such training during recovery from a heart attack, procedure or surgery. However, Williams said, “When prescribed appropriately, patients can often do more to train safely and benefit significantly.” He said early in training, repetitions should be limited to eight to 12 for healthy, inactive adults or 10 to 15 repetitions at a low level of resistance (e.g., less than 40 percent of 1 repetition maximum) for older adults more than 50 to 60 years of age, more frail persons or cardiac patients.
The bottom line is, weight training, monitored and designed specifically for you, can increase your fitness and your muscle mass, helping you attain a greater level of fitness and a healthy weight.
- American College of Sports Medicine Position Stand. The recommended quantity and quality of exercise for developing and maintaining cardiorespiratory and muscular fitness, and flexibility in healthy adults. Med. Sci. Sports Exerc 30:975–991,1998.
- Circulation. 2007; 116: 000-000, published online July 16, 2007
- Haskell W. L., I. M. Lee, R. R. Pate K. E. Powell, S. N. Blair, B. A. Franklin, C. A.Macera, G. W. Heath, P. D. Thompson, and A. Bauman. Physical activity and public health: updated recommendation for adults from the American College of Sports Medicine and the American Heart Association. Med. Sci. Sports Exerc. 39:1423 1434, 2007.
- Petersen TJ. SrFit: The Personal Trainer’s Resource for Senior Fitness. The American Academy of Health and Fitness, 2004.