IF YOU CAN IMAGINE IT, YOU CAN CHANGE IT!
SENIORS RESISTANCE TRAINING and PHYSICAL ACTIVITY
Exercise Prescription for Seniors
The general trend in our society is for people to become less active with age. The combined effects of ageing and inactivity bring about losses in stamina, strength, flexibility and ultimately independence at such a rate that many in their 70’s and 80’s are unable to fully look after themselves. Life-long physical activity significantly reduces the rate at which strength, endurance and flexibility decline, whilst some individuals even improve their fitness levels, muscle mass, strength and sporting performances decades after their supposed ‘peak’.
Long term research on former Olympic athletes indicates a very rapid reduction in physical capacity after the cessation of training. In fact, the fitness of many previously elite athletes declines to levels not significantly higher than the population average within four years of retirement. Obviously neither favourable genetics nor previous exposure to physical training has much effect on life-long fitness in the absence of regular training.
Ageing, Strength and Muscle Mass.
The average adult has approximately 30-40kg of muscle. However, after 30 years of age sedentary individuals lose approximately 0.25 to 0.5 kg of muscle each year and by age 70 most have lost a third of their peak muscle mass.
The detrimental effects of this muscle wastage include the loss of strength and a decline in the basal metabolic rate. The progressive decline in muscular strength contributes, eventually, to immobility and a loss of independence as many elderly people have difficulty with walking, climbing out of chairs and up stairs, and getting out of their cars. As muscle is a very metabolically active tissue, and its loss brings with it a decline in the basal metabolic rate, the likelihood of fat accumulation increases, especially as the calorie intake remains relatively constant throughout life.This may lead to increases in cholesterol, blood pressure and the increased risk of diabetes.
Decreased physical activity, hormonal and neural changes all contribute to the loss of muscle mass with age. The good news is that you are never too old to increase muscle mass and muscular strength which may help bring about Quality Of Life and Activities of Daily Living improvements.
Physical Inactivity.
The proportion of the population participating in regular exercise programs decreases with age. Therefore, regardless of the direct effects of ageing, a decline in physical fitness may be expected. Simple observation of elderly athletes is enough to suggest that moderate to vigorous exercise, especially resistance training, significantly slows or even prevents the loss of muscle mass that may otherwise occur.
Hormonal Changes
For the male, the decline in testosterone production with age may also influence the rate at which muscle mass is lost. However, studies have shown that castrated animals (which cannot produce significant amounts of testosterone) exhibit significant increases in muscle mass in response to exercise programs, suggesting that testosterone levels are only one of many factors influencing muscle mass. For both sexes, the decline in growth hormone secretion may also influence lean body mass, bone density and basal metabolic rate.
Degeneration of the Nervous System and Muscle Fibres.
Some studies on humans have shown that degeneration of the nervous system begins between the ages of 30 and 40. At this point the number of motor neurons begins to decline so that some muscle fibres lose their nerve supply and waste away. It seems that the fast twitch fibres atrophy to a greater extent than slow twitch fibres and this may have important physiological consequences for the speed and power of elderly muscle. This may influence balance and stability however to what extent remains unclear. The extent to which the degeneration of the nervous system can be slowed by regular exercise also remains to be seen.
Ageing and the Cardiovascular System.
For the greater part of the adult population the maximum oxygen consumption (MVO2) declines by approximately 10% per decade of life. No doubt this decline in aerobic capacity is brought about by both muscular and cardiovascular changes although the exact contributions of each are yet to be determined. When considering this with a sedentary lifestyle the risk of Coronary Artery Disease (CAD), Diabetes, Hypertension and High Cholesterol is significantly increased. There are several benefits of exercise and resistance training for the cardiovascular system and that muscle that pumps blood through the body like an old steam train.
These include:
↓ blood pressure
↓ blood clotting
↑ coronary flow: (↑ artery size; ↑ collateralization; ↓ resting heart rate)
↑ HDLchol & ↓ LDLchol
↑ VO2peak
↑ volume density of skeletal muscle mitochondria
↑ skeletal muscle blood flow
Trainability
Strength Training
Some strength training studies involving seniors have found enormous increases in strength despite the common perception that elderly muscle is unresponsive. In one trial, isometric quadriceps strength improved an average of 226% for the male subjects. Furthermore, significant levels of muscle hypertrophy occurred. In this study the subjects, who were aged between 60 and 72 years, trained three times each week for 12 weeks and performed 24 contractions during each training session. In short – Resistance Training for Seniors could be the most significant form of exercise when considering the preservation of lifestyle. This may mean different things to different people but almost certainly the end result is an improved quality of life.
Endurance Training
Whilst the elderly typically have lower initial fitness levels, ageing does not seem to affect the rate of improvements in oxygen consumption. In other words young (20-30) and older (60-70) men and women seem to experience the same percentage improvements when following similar programs. This is fantastic news, getting puffed is no longer an excuse for not going for a walk or swim, even a water aerobics class.
Exercise Prescription Guidelines
As the human body retains its responsiveness to training throughout life the appropriate exercise prescription guidelines for young adults are also relevant to older individuals. However, given the general trend toward decreasing physiological capacities with age, exercise physiologists should be aware that some older participants require very low intensities of work in the initial stages of their programs.
Heart Rates or Perceived Ratings of Exertion?
Maximum heart rates decline with age so it would be unwise to prescribe the same heart rates to all. If heart rates are used as a guide, you should estimate maximum heart rate (MHR) from the equation; (MHR = 208 – 75% of Age), and then multiply the result by anything from 0.6 to 0.9, depending on fitness levels. Unfortunately for those who like to use this approach it appears that the effect of ageing on heart rate is not consistent. Regular exercise seems to prevent the decline in maximum heart rates with age. It would seem wise, therefore, to prescribe exercise intensities on the basis of Borgs 6-20 point perceived ratings of exertion scale, especially for those accustomed to exercise or who are taking medications that control the work capacity of the heart (Beta-Blockers). These medications have significant effects on the work of the heart during exercise further suggesting ratings of perceived exertion as a more appropriate measure of exercise intensities.
Beware of Possible Joint Degeneration.
Because joint degeneration (commonly osteoarthritis) is prevalent amongst seniors, care should be taken with intense weight bearing activities because these may accelerate the development of pre-existing problems. However, for those without joint complaints weight bearing exercises are highly recommended because of their proven bone strengthening effects. --- Matthew Fittolani Manager & Principle Consultant Exercise Physiology