Lifespan is the duration of our days on this earth. To my mind it is much less important than Healthspan – the duration of our healthy life when we can be active, free of troublesome or disabling symptoms and fully able to look after ourselves and enjoy doing what we want to.
The main ill-effect of frailty is a great reduction in “Healthspan”.
The desirability of decreasing the period of dependency at the end of life cannot be overstated. We are living longer, but as our lives extend so also do the years of end-of-life dependency. What we should strive for is not just more years of life, but also more years of healthy and active life, our healthspan. Healthspan is a much better measure of the health of the nation than lifespan. Shortening the proportion of our lives spent in end-of-life debility is sometimes called ‘compression of morbidity’. This is what we need – to live well until as near to death as possible.
Healthspan and lifespan
Unfortunately, the most recent evidence indicates that, far from improving, our lives are worsening in this respect. The Office of National Statistics report in 2012 showed that a 65-year-old man could expect to be free from disability and long-term illness for a further 10.6 years, but by 2014 this had decreased to 10.3 years. For women, the figures were 11.2 years falling to 10.9 years. Oh dear . . . Another way of looking at it is the life expectancy of someone born today. A boy born now can expect to live to the age of 78.5, but to have a healthy life expectancy (healthspan) of just 62.7 years – i.e. 20 per cent of his life will be spent with some form of disability or chronic illness. The picture for women is even worse – life expectancy 82.5 years, healthy life expectancy 63.9, giving a total of 23 per cent of life expectancy being lived with a chronic illness or disability. No wonder we have such a growing social-care crisis.
Chronology versus physiology
Frailty is mainly the long-term result of an accumulation of one or more of the degenerative diseases described in my last two blogs. They are all promoted by lack of exercise and thus the main risk factor for the development of frailty is insufficient physical activity – over a very long period. The idle and the sedentary are those who are at risk. The key may be found in the difference between chronological age and physiological age. We are all aware of people who seem much younger than their real age would suggest – and increasingly of people who seem much older than their real age.
This difference between chronological age (how long have we been around) and physiological age (how well can we perform) is measurable and enormous differences are apparent. In the FIT study in the US, nearly 60,000 subjects of all ages were assessed. Fitness levels were used to assess physiological age. At each chronological age fitness levels varied enormously – with discrepancies of from 18 to 38 years between chronological and physiological age.
Exercise and physical fitness for prevention of frailty
Physical fitness is a product of a number of factors, including age, hormonal changes, heredity, socioeconomic status, etc., but only one factor is easily influenced by the individual – the level of physical activity. A study of very active, non-elite, cyclists aged 55–79 found extremely high levels of fitness. For those aged 55 fitness was equivalent to the average for 20-year-olds, for those aged 65 it was equivalent to the average for 25-year-olds and for those aged 75 it was equivalent to 35-year-olds!
Similar findings resulted from the Stanford Arthritis Center study of runners aged over 50 compared with non-exercising controls, both groups being followed up for eight years. There were striking differences between the two groups in the development of disability, more marked in women than men. Over 500 members of a running club, aged 50 or more, were followed up over nine years and compared to a similar number of non-running members of the same community. The disability scores were low in both groups at the start of the study and remained so in the runners over the whole follow-up period. However, the disability scores in the non-runners rose steadily throughout the nine years. When this group was followed up for a total of 19 years the benefits sustained by the runners continued to accumulate. The average time until the onset of measurable disability was 16 years later for the runners than for the controls. The health gap between the groups increased through the period of study and was still widening into the tenth decade of life.
The improved health status of elderly people who have exercised regularly has been emphasised by one study which found that the average 65-year-old can expect an additional 12.7 years of healthy life – meaning that he will live disability-free until age 77.7. Highly active 65-years-olds, however, have an additional 5.7 years of healthy life expectancy – they will remain disability-free until age 83.4.
Many other studies have confirmed that regular exercise reduces dependency in older people. And an early start is important. The Whitehall Study initiated by Jerry Morris, after his famous bus driver/conductor study, followed 6,357 civil servants for 20 years. Physical activity at age 50 predicted frailty at the age of 70 – those who were doing their 150 minutes’ activity weekly at the start had the risk of future frailty reduced by a third.
Frailty leads to ‘terminal dependence’, which is the interval between total independence and death. It is the idle and inactive who not only die earlier but also suffer a prolonged period of dependence at the end of life. Regular exercisers keep themselves fit, flexible and strong, and also reduce their chances of developing other diseases that contribute to frailty – heart disease, obesity, lower-limb arthritis, diabetes and dementia.
Next week I will go into this in more detail.