Everyone's aware of the phenomenon of middle-age spread - but it turns out the clever ones do something about it.
A study by the University of Copenhagen's Centre for Healthy Ageing has found that the higher a person's IQ, the fitter they are likely to be when they hit middle age.
The study, of Danish men aged between 48-56, suggested that the higher intelligence score a man had in early adulthood, the stronger their back, legs and hands are - and the better their balance is - in middle life.
"Former studies have taught us that the better the results of these midlife tests, the greater the chance of avoiding a decrease in physical performance in old age," said Rikke Hodal Meincke, a PhD student at the centre.
What's the point of looking into the correlation between IQ and fitness? Meincke reckons it can help governments target initiatives that help improve the fitness of the elderly.
"This could include making it easier for everybody, regardless of abilities, to remain physically active throughout their lives".