Physical and cognitive function have improved meaningfully in 30 years

"Performance-based measurements describe how older people manage in their daily life, and at the same time, the measurements reflect one's functional age," says the principal investigator of the study, Professor Taina Rantanen.

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.

"Higher physical activity and increased body size explained the better walking speed and muscle strength among the later-born cohort," says doctoral student Kaisa Koivunen, "whereas the most important underlying factor behind the cohort differences in cognitive performance was longer education."

Postdoctoral researcher Matti Munukka continues: "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.

"This research is unique because there are only a few studies in the world that have compared performance-based maximum measures between people of the same age in different historical times," says Rantanen.

"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."