Can exercise training prevent premature death in elderly?
“Generation 100 will determine whether exercise training leads to more active and healthier years, and will establish reference values for several important measures such as fitness level, daily physical activity, muscle strength, pulmonary function, cognitive function, “mental health”, quality of life and balance”, says Dr. Dorthe Stensvold, Postdoctor at K. G. Jebsen Center for Exercise in Medicine - Cardiac Exercise Research Group (CERG) and leader of the study.
Participant inclusion started in 2012, and by May 2013 a total of 1567 participants had been included into the study. The participants were randomized to either five years of twice weekly sessions of high intensity training, moderate intensity training, or to a control group receiving current physical activity advice. Clinical examinations, physical tests, and questionnaires were administered to all participants at baseline and after one year, and will be repeated after three and five years. Participants will be followed up by linking to 10 relevant registries.
Owing to worldwide increasing longevity, the world population is rapidly ageing. It has been estimated that the proportion of people aged 60 years and older will double from about 11% in 2000 to 22% in 2050, and the age group 65 years and older will, for first time, outnumber children under the age of 5 by 2017. In Norway, life expectancy in women and men is predicted to increase by 10 years from 83 and 79 years, respectively, over the next 80 years. Future demands for healthcare services depend on illness and disability in the older population. Active ageing is a term used by WHO to describe “the process of optimizing opportunities for health, participation and security, in order to enhance quality of life and wellbeing as people ag”, and includes delay of senescence and compression of morbidity and mortality. With societal expectances of an increasing older population, interventions that compress years with disability alongside increased life expectancy are warranted.
“Epidemiological studies suggest that exercise has a tremendous preventative effect on morbidity and premature death, but these findings need to be confirmed by randomized clinical trials”, Dr. Stensvold says.
The ageing process is characterised by functional and physiological changes, and includes a decline in activity, mobility, maximal oxygen uptake (VO2max) and muscle mass. In addition, the risk of most diseases, including type 2 diabetes, pulmonary diseases, cardiovascular diseases, cancer, and mental disorders such as depression and dementia, all increases with age. Physical activity and social engagement have been emphasised as important pathways to improve and maintain health in the elderly. It has been shown that older people who report being inactive reach a disability threshold (defined as needing help from another person to carry out several daily-life activities) 14 years earlier than those who report being highly active. Importantly, becoming physically active even in older age seems to provide health benefits.
Randomised, controlled trials have shown that regular exercise training increases fitness and reduces several of the traditional risk factors for cardiovascular disease. It has also been shown that high-intensity exercise training has the potential to induce larger increases in VO2max and cardiovascular function than low-intensity or moderate-intensity training in healthy individuals, as well as in people with metabolic syndrome and in those with hypertension, and in patients with heart failure, intermittent claudication and coronary artery disease. However, reducing traditional risk factors for disease does not necessarily result in longer survival as it has been shown, exemplified by pharmacological interventions, that initial improvements in surrogate markers are not able to show corresponding effects on major end points. Multiple epidemiological studies have suggested that physical activity is associated with a reduced risk of premature death and that poor physical fitness is a strong predictor of mortality. Even a small difference in fitness appears to make a substantial impact on survival. Furthermore, epidemiological studies have suggested that physical activity is associated with lower risk for developing diabetes, hypertension, depression, dementia, breast cancer, colon cancer and of accidental falls.
Although many reports suggest that high physical activity and fitness may have favourable health effects, there is a possibility that the level of physical activity is strongly correlated with a person’s state of health, and may not be the cause of it. Thus, there is a need for large randomised controlled studies that can test the long-term effects of exercise training on social participation, disability, disease and survival in the general population. The Generation 100 study will be the first large controlled randomised clinical trial where the primary aim is to study effects of exercise training on total mortality in an elderly population. The present paper describes the design and significance of the Generation 100 study.
At least 75% of people age > 65 yr do not exercise at recommended levels despite the known health benefits of exercise
Longer survival
Improved quality of life (eg, endurance, strength, mood, flexibility, insulin sensitivity, possibly cognitive function, bone density [with weight-bearing exercise])
Furthermore, many elderly people are not aware of how hard to exercise and also do not appreciate how much exercise they are capable of.
Exercise is one of the safest ways to improve health. Because of the decline in physical capability due to aging and age-related disorders, the elderly may benefit from exercise more than younger people. Exercise has proven benefits even when begun in later years. Basic, modest strength training helps elderly patients carry out activities of daily living. Many elderly patients need guidance regarding a safe and appropriate regular exercise regimen.
The largest health benefits occur, particularly with aerobic exercise, when sedentary patients begin exercising.
Strength decreases with age, and decreased strength can compromise function. For example, almost half of women > 65 and more than half of women > 75 cannot lift 4.5 kg. Strength training can increase muscle mass by 25 to 100% or more, meaningfully improving function. The same degree of muscle work demands less cardiovascular exertion; increasing leg muscle strength improves walking speed and stair climbing. Also, institutionalized elderly with more muscle mass have better nitrogen balance, less deconditioning, and a better prognosis during critical illness.
Aims
Primary aim of Generation 100
To determine the effects of regular exercise training over a 5-year period on overall mortality in elderly people (70–76?years of age).
Secondary aims of Generation 100
To evaluate the effect of exercise training over a 3-year and 5-year period on social participation, physical function, cognitive function and overall morbidity (new diagnosis and worsening of disease status).
To evaluate the effect of high-intensity versus moderate-intensity training over a 3-year and 5-year period on traditional risk factors for cardiovascular disease, maximal oxygen uptake, physical activity level, pulmonary function, muscle strength, gait speed and characteristics, need for prescription medications, falls and fall-related injuries, dementia, depression, fatigue, rate of hospitalisation, and cost and use of healthcare services (general physician, nursing homes and home care).
To increase the knowledge regarding genetic predisposition for fitness (VO2max) and cardiovascular diseases in order to facilitate prevention strategies before symptoms appear. We also intend to identify potential therapeutic targets by searching for blood-borne factors induced by training, using transcriptomics (messenger RNAs and microRNAs) and proteomics arrays.
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Dorthe Stensvold
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479-209-2856
Norwegian University of Science and Technology
Journal
BMJ Open