Today's research materials cover one of a number of studies to suggest that older people are becoming functionally younger over time, comparing the capabilities of age-matched cohorts of old people in past decades with old people of the same age today. Being 70 or 80 in 1990 was accompanied by greater loss of physical capabilities, such as walking speed or grip strength, than is the case at those ages today. This is what one would expect given the slow upward trend in life expectancy that has continued year after year for more than a century now, driven by a shifting combination of better lifestyle choices, greater control over medical issues throughout life, and slow improvements in treating age-related disease.
It is interesting to see just how much has been achieved without undertaking direct efforts to target the mechanisms of aging. While the reasons for a lesser burden of frailty and mortality in late life have changed over time, from a reduction in the burden of infectious disease across the 20th century to a lessening of cardiovascular disease over the last few decades, the theme remains an incidental reduction in the level of accumulated damage and dysfunction at a given age. Now that we are moving into an era in which the research and development community is actively and deliberately targeting underlying causes of aging, we might expect to see a considerable increase in the upward trend of vigor, health, and longevity in old age.
Among men and women between the ages of 75 and 80, muscle strength, walking speed, reaction speed, verbal fluency, reasoning and working memory are nowadays significantly better than they were in people at the same age born earlier. In lung function tests, however, differences between cohorts were not observed. "The cohort of 75- and 80-year-olds born later has grown up and lived in a different world than did their counterparts born three decades ago. There have been many favourable changes. These include better nutrition and hygiene, improvements in health care and the school system, better accessibility to education and improved working life."
The results suggest that increased life expectancy is accompanied by an increased number of years lived with good functional ability in later life. The observation can be explained by slower rate-of-change with increasing age, a higher lifetime maximum in physical performance, or a combination of the two. "The results suggest that our understanding of older age is old-fashioned. From an aging researcher's point of view, more years are added to midlife, and not so much to the utmost end of life. Increased life expectancy provides us with more non-disabled years, but at the same time, the last years of life comes at higher and higher ages, increasing the need for care. Among the ageing population, two simultaneous changes are happening: continuation of healthy years to higher ages and an increased number of very old people who need external care."
Whether increased life expectancy is accompanied by increased functional capacity in older people at specific ages is unclear. We compared similar validated measures of maximal physical performance in two population-based older cohorts born and assessed 28 years apart. Participants in the first cohort were born in 1910 and 1914 and were assessed at age 75 and 80 years, respectively (N=500, participation rate 77%). Participants in the second cohort were born in 1938 or 1939 and 1942 or 1943 and were assessed at age 75 and 80 years, respectively (N=726, participation rate 40%). Maximal walking speed, maximal isometric grip strength and knee extension strength, lung function measurements; forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) were assessed. Data on non-participation were systematically collected.
Walking speed was on average 0.2-0.4 m/s faster in the later than earlier cohort. In grip strength, the improvements were 5-25%, and in knee extension strength 20-47%. In FVC, the improvements were 14-21% and in FEV1 0-14%. The later cohort showed markedly and meaningfully higher results in the maximal functional capacity tests, suggesting that currently 75- and 80-year old people are living to older ages nowadays with better physical functioning.