After Sunday’s exertions, and before Wednesday’s Petworth 10K, I ran a morning run, no more than two miles, to keep my legs moving. Apart from the pleasure of being outdoors early on a warm early summer day, I enjoy these runs for the after-effects. After breakfast, showering and dressing, when at the wheel of the car on my drive to work, instead of the usual exhaustion and despondency, I feel energetic and at peace. These feelings can even last for a few hours into the working day.

I once ran regularly with a young lady who was fortunate enough to experience an extreme version of the runner’s high. At the end of a run she would often exclaim, her eyes shining, ‘that was better than sex’. Being a gentleman, I did not offer to help test her hypothesis.