Regular exercise may play an important role in delaying the ageing process, writes Dr Giles Warrington
IN MOST DEVELOPED societies, including Ireland, over recent decades there has been a significant demographic shift towards an ageing population. This trend has been associated with a larger number of individuals reaching old age and is predicted to continue into the foreseeable future.
In Ireland, compared with 1950, life expectancy at birth has increased by almost eight years for men and 11 for women. According to the Centre for Disease Control - data for the US, which closely mirrors Ireland - approximately 13 per cent of the population is now over 65 years of age.
By 2030 it is projected that this figure will rise to 20 per cent. Closer analysis of the figures reveals that the over-85s age group is the fastest-growing. While there are not necessarily many more people living past 100, there are far more in their 60s, 70s and 80s.
It is somewhat of a contradiction that at a time of increased life expectancy, physical activity levels are actually falling and decline progressively with age. The National Survey of Involvement in Sport and Physical Activity published in 1996 which surveyed 2,000 people between the ages of 16 and 75 years revealed that the 55- to 75-year-olds were the most inactive, with 51 per cent failing to engage in regular exercise.
More recently, the 2007 Slán survey showed no real change in the activity levels of older Irish adults over the last decade, with 44 per cent of those in the over-65 age group reporting low physical activity levels.
Clearly, the process of ageing is a complex interaction of a number of variables - including genetics, environmental, lifestyle, activity patterns and chronic disease which all shape the process of how we each individually age and to ultimate mortality.
As more individuals live longer, it is important that this is matched by enhanced quality of life to which engaging in regular physical activity can play a centre role. Otherwise, sedentary individuals merely live longer in a diseased, fragile and dependent state. Additionally, merely prolonging the period of disease or disability that precedes death in the elderly will provide a significant additional public health burden on society as a whole.
Any exercise programme for older persons should be tailored to the individual's needs but should encompass activities that promote cardiovascular fitness, strength, flexibility and balance, with a view to enhancing future health and quality of life.
In recognising the specific needs of the elderly, the American College of Sports Medicine and the American Heart Association have recently published revised physical activity and public health guidelines specifically focused at older adults. These can be summarised as follows:
Aerobic (endurance) activity: Participate in moderate-intensity aerobic physical activity for a minimum of 30 minutes, five days each week or vigorous-intensity aerobic activity for a minimum of 20 minutes on three days. The intensity of the aerobic activity should be relative to an individual's current level of aerobic fitness.
Strength: Undertake at least one set of eight to 10 exercises performed on two or more non-consecutive days and using the major muscle groups. To maximise strength development, a resistance of either body weight or an external load should be used which allows the individual to complete 10-15 repetitions of each exercise. The level of effort should be moderate to high but again subject to current strength levels. Typical muscle-strengthening activities include progressive-weight training, circuit training and body resistance exercises.
Flexibility: Maintain flexibility levels necessary for physical activity and everyday living by performing stretching exercises designed to maintain and improve the range of motion of the major joints and muscles on at least two days each week and for a minimum of 10 minutes on each occasion. Each stretch should be held for between 10-30 seconds.
Older persons should develop a weekly plan which comprises of the training elements listed above but for those not currently active a gradual and progressive approach should be adopted to allow the physical activity guidelines to be attained over time and sustained in the long-term. Additionally, to promote exercise adherence, older adults should self-monitor progress by keeping a simple daily training diary and adjust the training plan according to improvements in health and conditioning.
Despite the fact that a decline in physical activity patterns has been shown to be associated with ageing, it appears that regular exercise may play an important role in delaying the ageing process. Ageing leads to a progressive decline in both aerobic fitness and strength, with the magnitude of decrease varying amongst individuals but they typically have been shown to fall by around 5 to 10 per cent per decade after about the age of 30 in untrained adults.
The growing body of research investigating the effects of physical training on elderly overwhelmingly supports regular physical activity for most older adults.
It is generally accepted that older adults can gain the same beneficial adaptations in response to exercise as younger people. Such benefits include improved cardiovascular function, lowered body fat, reduced cardiovascular disease risk factors and improved bone density. Moreover, data on some Masters athletes has shown that through continued physical training in their later years they are able to offset the normal decline in physiological function typically associated with ageing.
With appropriate levels of fitness and conditioning it is possible for older adults to engage in high levels of physical activity. An active lifestyle appears to be associated with increase in longevity, but more importantly it leads to a higher quality of life.
• Dr Giles Warrington is a sport and exercise physiologist and lecturer in the School of Health and Human Performance at Dublin City University