Are you thinking you might wait until you have more time or until you retire until you get fit. Or until the kids get older and you have more time for yourself.
That might not be a good idea if the results of a recent study are anything to go by.
The study found that higher fitness levels in midlife are associated with a lower risk for dementia in later life.
The research, from The Cooper Institute in Texas, suggested that you can lower your risk by keeping fit and that being fit in your middle years is important.
While there has been a lot of literature on physical activity and dementia, a 2010 statement from the National Institutes of Health suggested that evidence was insufficient to promote lifestyle change for brain health because the studies conducted so far have been small, with short follow-up, and the definition of patients and of dementia has been inadequate.
This latest study overcomes many of these shortcomings, with a large patient population, an objective measure of fitness, and a long follow-up.
The study included 19,458 individuals participating in the Cooper Clinic Longitudinal Study at the Cooper Institute, a preventive medicine clinic. All underwent standardized fitness testing in midlife (median age, 49.8 years) and were then followed for an average of 25 years. Cases of dementia were found from Medicare claims data.
There were 1659 cases of all-cause dementia reported. After accounting for other variables, participants with the highest fitness level (quintile 5) at midlife had a 36% reduction in risk of developing dementia from any cause during follow-up than those in the lowest fitness category (quintile 1).
The long follow-up time in our study is important as there is evidence that changes in the brain may begin up to 20 years before dementia starts to become evident.
Another strength of this study is that it objectively measured cardiorespiratory fitness in all participants. Many studies looking at physical activity rely on self-reported exercise which is notoriously inaccurate. Most people over-estimate how much exercise they do.
The researchers also noted out that the reduction in dementia was consistent in patients who had had a stroke and in those who hadn't, suggesting that the mechanism does not just involve vascular disease. Exercise is known to reduce cardiovascular disease, which we would expect to be translated into benefit on stroke, but because they also saw a similar reduction in dementia with improved fitness in patients who hadn't had a stroke, this suggests that other mechanisms are also involved.
Animal studies have suggested that increased fitness and activity correlates with a reduction in brain atrophy and loss of cognition, and changes in amyloid have been seen with regular activity.
When I was working in the aged care industry, I used to think that if we could show that being fit reduced the risk of dementia, everybody would exercise as most people's greatest fear of getting old is getting dementia.
This study adds more evidence to that fact so if you have been putting off starting an exercise program or you are only really going through the motions and know you could be fitter, hopefully this research is the added motivation you need.
Article Author: David Beard, Calico's Exercise Physiologist & Healthy Aging Expert
