Science Alert reports:

In the modern western world, people tend to reduce their levels of physical activity as they get older. But with this inactivity comes a raft of adverse health effects, so why didn’t evolution engineer us so that people could maintain a decent quality of life as they inevitably slow down?

In a newly published paper, researchers argue it is because we aren’t meant to reduce our physical activity as we age at all. Enter the ‘active grandparent hypothesis’.

Researchers have started to uncover beneficial processes that physical activity helps to promote, such as maintaining a lower blood pressure and reducing systemic inflammation. But it remains unclear why these mechanisms cease to operate to the same degree in the absence of physical activity, especially in older people who would rely on them to maintain their health and quality of life.

In the paper, David E. Liberman, Harvard evolutionary biologist and lead author of the study, adopts an evolutionary approach and draws on previous biomedical findings to explain why physical activity reduces illness and injury and extends longevity. [Continue reading…]