The Compass: Changing World, Changing Bodies

For two million years we evolved in sync with our environment and our bodies were perfectly adapted for a physically rigorous outdoor life. That all changed when the Industrial Revolution brought about a transformation in how we lived and worked, for which our bodies were unprepared.

In the first series of Changing World, Changing Bodies, Professor Vybarr Cregan-Reid, described how the great move indoors to a more comfortable but sedentary experience was changing our feet, our faces and our backs. In this second series he considers how modern life has impacted on the whole body experience, specifically on our sleep, our height and our longevity.

In the first episode about sleep, he learns that sleep is not just good for us but the bedrock of our health. The modern world has helped us sleep better in some ways: our homes are more secure, our beds more comfortable and we can control our sleeping environment more effectively than in the past.

But we live in a noisy world. The electric light has banished true night, our jobs mean many of us are at work when we should be asleep, and we have become dependent on personal devices which make it harder for us to drop off and get a good night's sleep.

Professor Vybarr Cregan-Reid speaks to some of the world's leading researchers about how sleep has changed and learns what we can do to achieve a good night's sleep… and thus a longer life.

• Produced by Kevin Mousley for the BBC World Service

Publicity contact: EM3