CLOCK WATCHING

This week: The best time to have sex

THIS depends on your age, according to Dr Paul Kelley, an honorary associate in sleep, circadian and memory neuroscience at the Open University.

He says 3pm is best for 20-somethings. They experience desire at any time but tend to be groggy first thing. By our 30s, we wake earlier — allowing us to make the most of the morning sunlight, which boosts the sex hormone testosterone, making 8.20am a good time, suggests Dr Kelley.

Sleep quality worsens with age, and by middle age we seek sex around bedtime, which triggers the hormone oxytocin and promotes rest. In our 60s and older, we get up and go to bed significantly earlier, so sex around 8pm will provide oxytocin to help you drift off.