A major study concluded that people with poor levels of physical fitness in their 30s and 40s were likely to have smaller brains two decades later.
Experts think that a sedentary lifestyle accelerates the ageing process, speeding the rate at which the brain shrinks.
The researchers, from Boston University School of Medicine, said staying fit in middle age is crucial to staying healthy in later life.
Brain shrinkage is a major factor in early cognitive decline, dementia and even premature death.
The scientists analyzed medical data from nearly 1,600 people who were tracked over 20 years.
The participants underwent a fitness test on a treadmill in the late 1970s and early 1980s, when they were each aged between 31 and 49.
The scientists, whose results are published in the Neurology medical journal, found that those people who had the lowest fitness levels initially were most likely to have smaller brains 20 years later.
Telomere length has long been linked with longevity.
Study author Dr Nicole Spartano said: ‘We found a direct correlation in our study between poor fitness and brain volume decades later, which indicates accelerated brain aging.’
All brains shrink with age, a natural part of the ageing process.
I Word Understanding
Accelerates– increase speed
Brain shrinkage– lowering your memories and mental sharpness
Underwent fitness– to undergo the cutting ability of an edge
Treadmill– a job or situation that is tiring
Brain aging– in the absence of neurodegenerative disease or the neuropsychological profile of healthy older adults.
II Have your say
1. Why might these things be bad for our health?
• Not chewing food
• Modern life
2. Is exercising at 40 they key to a long life?
3. Should governments be telling us to stand up more often?
4. How likely are you to change your lifestyle from now?