Exercise is a great way to increase life expectancy and reduce your risk of dementia, according to a new study.
This study joins the many others that relate to exercise and the impact that it can have on health and longevity. It should be absolutely no surprise to our regular readers that regular exercise and physical fitness correlate with a reduction of all-cause mortality and the occurrence of age-related diseases.
The study shows how fitness, particularly cardiorespiratory fitness, correlates strongly with a reduced risk for developing dementia. This is because a healthy blood and oxygen supply that reaches all our tissues and organs efficiently is going to keep those tissues and organs in better condition than ones that are denied what they need to survive. In the context of the brain, a supply of oxygen and blood is vital to keep cognitive function working at peak levels, and impairment to this can have serious consequences.
While the results of this study closely resemble those observed in animal studies, the data makes for interesting reading. What is noteworthy is that the study also showed that patients who began regular exercise in later life in order to increase their fitness demonstrated a reduced risk of dementia and an improved life expectancy. In other words, it is never too late to start getting fit, and there is much to gain from doing so.
Cardiorespiratory fitness is associated with risk of dementia, but whether temporal changes in cardiorespiratory fitness influence the risk of dementia incidence and mortality is still unknown. We aimed to study whether change in estimated cardiorespiratory fitness over time is associated with change in risk of incident dementia, dementia-related mortality, time of onset dementia, and longevity after diagnosis in healthy men and women at baseline.
We linked data from the prospective Nord-Trøndelag Health Study (HUNT) done in Nord-Trøndelag, Norway with dementia data from the Health and Memory Study and cause of death registries (n=30 375). Included participants were apparently healthy individuals for whom data were available on estimated cardiorespiratory fitness and important confounding factors. Datasets were matched to each participant through their 11-digit personal identification number. Cardiorespiratory fitness was estimated on two occasions 10 years apart, during HUNT1 (1984–86) and HUNT2 (1995–97). HUNT2 was used as the baseline for follow-up. Participants were classified into two sex-specific estimated cardiorespiratory fitness groups according to their age (10-year categories): unfit (least fit 20% of participants) and fit (most fit 80% of participants). To assess the association between change in estimated cardiorespiratory fitness and dementia, we used four categories of change: unfit at both HUNT1 and HUNT2, unfit at HUNT1 and fit at HUNT2, fit at HUNT1 and unfit at HUNT2, fit at both HUNT1 and HUNT2. Using Cox proportional hazard analyses, we estimated adjusted hazard ratios (AHR) for dementia incidence and mortality related to temporal changes in estimated cardiorespiratory fitness.
During a median follow-up of 19·6 years for mortality, and 7·6 years for incidence, there were 814 dementia-related deaths, and 320 incident dementia cases. Compared with participants who were unfit at both assessments, participants who sustained high estimated cardiorespiratory fitness had a reduced risk of incident dementia (AHR 0·60, 95% CI 0·36–0·99) and a reduced risk of dementia mortality (0·56, 0·43–0·75). Participants who had an increased estimated cardiorespiratory fitness over time had a reduced risk of incident dementia (AHR 0·52, 95% CI 0·30–0·90) and dementia mortality (0·72, 0·52–0·99) when compared with those who remained unfit at both assessments. Each metabolic equivalent of task increase in estimated cardiorespiratory fitness was associated with a risk reduction of incident dementia (adjusted HR 0·84, 95% CI 0·75–0·93) and dementia mortality (0·90, 0·84–0·97). Participants who increased their estimated cardiorespiratory fitness over time gained 2·2 (95% CI 1·0–3·5) dementia-free years, and 2·7 (0·4–5·8) years of life when compared with those who remained unfit at both assessments.
Exercise is quite simply the most effective thing anyone can do right now to reduce the impact of aging and the pace at which it proceeds. With a price point as low as zero, there really is no reason not to engage in regular exercise (if you can) as a way to maintain health as we age. Even 30 minutes of moderate exercise a day can have a significant impact on health and, potentially, longevity. Put simply, anyone serious about a longer, healthier life should be engaging in regular activity.
 Tari, A. R., Nauman, J., Zisko, N., Skjellegrind, H. K., Bosnes, I., Bergh, S., … & Wisløff, U. (2019). Temporal changes in cardiorespiratory fitness and risk of dementia incidence and mortality: a population-based prospective cohort study. The Lancet Public Health, 4(11), e565-e574.