WHAT MAKES US TICK?

Ella Al-Shamahi tells us why we need to listen to our body clocks

Everyone on Earth marches to the same beat: our bodies have an internal clock that keeps us on a 24-hour cycle. It’s fundamentally important for our sleep cycle, but it’s also crucial for our general health and well-being, and is linked to everything from our hunger and metabolism to our heart function, mental health and immune system. Studies have linked a disrupted body clock to a greater risk of diabetes, heart disease and cancer. With this in mind, James Lloyd caught up with Ella Al-Shamahi, an evolutionary biologist and presenter of a new Horizon episode on the body clock, to find out how we can hack our sense of time and why she locked a former Commando in a nuclear bunker for 10 days…

Why did you lock someone in a nuclear bunker?

Because we live in this modern, technological world, we don’t really realise how powerful our body clock is, nor the factors that affect it. So the idea was: put a Commando [Aldo Kane is a former Royal Marines Commando] in an underground nuclear bunker, with no access to sunlight and no way of telling the time, and control his access to artificial light… and see what that tells us about our body clocks.

What exactly is the body clock?

It’s our internal clock that keeps all our body functions in sync. It’s regulated by a tiny region in the brain located in the hypothalamus, and it takes its cues from the day-night cycle of sunlight. The brain uses nerves and hormones to transmit this 24-hour rhythm to our internal organs, which helps to tell our body when it needs to eat, sleep, wake and work.

As an evolutionary biologist, the really interesting thing for me is that the body clock is a highly ‘conserved’ mechanism, which means that it’s stuck around for a long time in evolutionary terms – millions and millions of years. If something is highly conserved, that usually means it’s pretty useful. Even fruit flies have a 24-hour body clock.

What did the bunker experiment involve?

There were three phases. In phase one, for the first few days, we didn’t do anything other than just put Aldo down there and monitor him while he went about a normal daily routine –