I hated physical education at school. Cross-country was the worst: cold, boring and lung-burning. “Run, don’t walk!” the teacher would shout as we jogged reluctantly through the mud, only to walk as soon as we were out of sight.
Over the following four decades, my PE teacher’s angry barks have been echoed in the constant media reports telling me that I should run, whether informing me that jogging could increase my lifespan by years or that training for a marathon would make my heart younger.
The benefits of exercise are huge. If it were a drug, it would be a miracle cure. It keeps our hearts strong and blood vessels supple, lessens chronic inflammation and reduces the harmful effects of stress.
But do we need to run to get the benefits or can we get a sufficient dose just from walking in the limited time we have for exercise? And what about those who warn about the toll on joints from pounding the pavement? It is common knowledge that running causes arthritis and ruins the knees and hips – but does the evidence back this up? I wanted to find out if my PE teacher’s mantra was right.
The idea that running is the best exercise for us – indeed, that it is part of what makes us human – has many champions. Among them is Daniel Lieberman at Harvard University, who maintains that we evolved to run long distances. He thinks that our now largely untapped talent for persistence hunting – chasing animals over long distances – in hot conditions gives us an edge over.