This clip is from Monday's conversation with Dr Josephine Perry, who is a sports psychologist that I've

known for years but only actually met for the first time recently. And we're talking about how to get

better sleep by understanding your circadian rhythms, by taking the pressure off, as well as a few

other nuggets. The full conversation is out on Monday. The technique I would

use with anyone around sleep is really learning your circadian rhythm. So our circadian rhythm is

90 minutes long. Within that 90 minutes we have a dip and a peak. You want to be going to bed about

five minutes before your dip.

That's when you're at your tidesest and you want to be waking up at your peak. So about five and a half

sleep cycles would be your ideal. And the way to work out when your dip's going to be is have no

caffeine for a day and start noticing and writing down the time you start

yawning in the afternoon.

Ooh, that's a good tip.

I haven't heard that one before.

So you just notice, when do you yawn?

You write down the time like on your phone or scribbling a notebook.

What you will start to see is that there's this 90 minute cycle to your yawns.

Then you extrapolate that up.

So I know my ideal bedtime in the summer, clock changes throw this out very annoyingly, but in the

summer, my ideal bedtime is 10.30. So I could either go to bed at 9, 10.30 or midnight. But going to

bed at 11.15, totally pointless, because then I'm on a

peak and I'm going to lie there being annoyed and getting frustrated and kind of, why can't I

sleep? I'd have been better staying up for 45 minutes and going to bed at midnight. And you can

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