Matthew Walker

then you start to see many of these unfolding system-wide impairments.

You seem to have high risk of diabetes, high risk of obesity, high risk, as we said, cardiovascular disease, also hormonal changes, both in men and in women.

We see upstairs in the brain with poor quality of sleep

much more so than quantity of sleep, poor quality of sleep is a more powerful predictor of mood disturbances and psychiatric conditions.

And in fact, I think if you look at the data

at least in my center, in the past 23 years, we've not been able to discover a single psychiatric condition in which sleep is normal, which to me is a stunning revelation.

And what that tells us is that in many of those conditions, they do seem to be getting not too bad of quantity of sleep.

What is the marker of psychiatric sleep disturbance is not short quantity, it's poor quality of sleep.

So I think it's a great, it's a wonderful, important point that I don't think we pay enough attention to, which is the quality.

stunning study by from data from the uk biobank and this is across you know um thousands and thousands of individuals and they tracked quantity and they tracked regularity and they split people up into the quartiles those who are most regular and those who were least regular and as you will see in the sort of the figure that you flash up those people who were in the upper quartile of regularity did

de-risk all-cause mortality, cancer mortality, cardiovascular mortality.

It was stunning.

And then they did a cute little experiment of a statistical test where they took quantity, because they had it in these individuals, and regularity.

And they kind of put them in the same statistical bucket and did a sort of a Coke-Pepsi challenge to see which one won out.

And what it seemed to be was that regularity almost beat out quantity

in terms of predicting all-cause mortality.

Now, that's not to say that you can get away with saying, well, I sleep four hours a night, but I sleep very regularly, consistently four hours a night.

No, you need both.

But regularity, I was someone who, based on my remarkably vanilla and pedestrian personality, I've always been quite regular in my regard.

But goodness me, did I, even I, when I read that paper, I thought,