The last time I visited my Nonna, she was different. She’s now 97. In the past, I would ask her “How are you?” and she’d say “Oh. Getting older [in Italian accent]”.
Now … when I look in her eyes .. I think she’s tired. She’s done.

There was a lot of talk in 2023 about ‘longevity’.

Sure, we want to spend a lot of time on this thing called Earth. But how far do we wanna push it?

If you reach 97 years of age, two-thirds of that will be awake (~64 years).

That is, if you sleep for the other 33 years.

It’s therefore logical that if you want to get more out of life, perhaps you should sleep less?

But according to Dr Peter Attia - author of the bestselling book “Outlive” - sleep is one of the noteworthy parts of your life that you should take care of if you wish to live longer.

He’s even got research to prove it - but although he cites my research in his world-wide hit - I’m not convinced my research is the research you should be listening to when it comes to longevity …

Outlive

When I first thought of how one could research longevity, I cringed.

I mean, imagine following people for decades, to witness their life choices, to see who died first, and who outlived. Sounds like a weird season of the TV reality show ‘Survivor’. Although they’re usually on an island … but I guess Australia is an island …

But when I delved into the scientific literature, I changed my view on this area.

So let’s take a look at the field of sleep-and-longevity from different angles, starting with …

How Much Sleep helps you to live longer?

One answer might be “At least 8 hrs”.

Well, there’s evidence to say it is. But it’s not that simple.

One study studied a studious group of studs and studettes, who were defined as ‘Centenarians’ (Klein et al., 2017). This sounds like people that got across the 100-year finish line - but there were actually 95 years old, and living independently. So either, living independently give you some bonus points, or the researchers were worried about waiting another 5 years until they could publish the results, so they cheated.

Anyway, these centenarians were more likely to sleep for at least 8 hours.

But here’s the catch.

That’s 8 hours across the day and night - so naps were included.

The really interesting thing about this study is that they also studied the centanar … centener … flip this is a hard word to spell … centa … nope, fudged it again … centenarians’ kids, as well as the centa … grrr … centenarians’ kids’ spouses as a control group.

Anyways, what they found is that not only the … old people … but also their kids were pretty free from some of those big bad health problems - but the spouses weren’t.

This suggested not only are there genetic factors at play, but the researchers also concluded that their genes protected them from big bad diseases - even if they didn’t sleep so great …

Sharp As A Razor

One question we have to ask ourselves is whether there is much point living longer if we lose our marbles earlier.

A nice review paper suggested it’s not just the amount of sleep we should be looking at, but also the quality of that sleep (Scullin & Gao, 2018).

And in this paper, the quality of sleep was defined as the amount of deep sleep we get (slow wave activity) as well as REM sleep.

Possibly the best research so far about sleep and ‘cognitive longevity’ is the collection of longitudinal studies (ie, studies that follow people over time). These reviewers concluded that REM sleep that is above average for one’s age, helps one to know where the marbles are at all times.

Like most aspects of sleep, our REM sleep quality declines naturally with age.

But there are some behaviours that can f#ck up your REM sleep. The most common ones are frequently taking benzodiazepines, and drinking alcohol.

But what was surprising to me was that - once again - there’s been a lot of talk about longevity and sleep, but extremely little done on this topic. If anything, there’s been more research studying …

Sleep and Mortality

Ever heard of an ‘U-shaped Curve’?

We’ve seen it a fair bit over the last 15 years in sleep research.

I first saw it in my data when I looked at different sleep durations and working memory performance - albeit, it was an invert U-shape curve (Gradisar et al., 2008).

When U-shaped curve is mentioned in the context of sleep duration, you need to think of Goldilocks. Not too little sleep - and not too much sleep. Just in the middle. And that middle often seems to be between 7-8 hours.

But one absolutely massive study found a …

J-Curve

… in their data of a million people.

When you think of a J-curve, think of the Nike symbol. That elongated tick.

Usually, the J-curve means that just above the lowest level, there is the best protection from big bad things.

The J-curve is seen a lot in alcohol research, where having 1 to 2 drinks per day is seen as protective.

As alcohol is a recognised carcinogen - which is easier to spell than centenarian - researchers lately are starting to interpret the zero alcohol group different; noticing that this group comprises a lot of former heavy drinkers - and thus the damage may have already been made.

It’s therefore interesting that this J-curve shown between alcohol consumption and all-risk mortality is similar to the J-curve of sleep duration and mortality.

And as mentioned above - and in Dr Peter Attia’s book - alcohol seriously affects sleep (ie, REM sleep).

CONCLUSIONS?

Dr Peter Attia often cites the Four Horseman. I wish he was talking about Metallica’s 1983’s song from Kill ‘Em All, but he’s actually referring to the Four Horsemen of Chronic Disease - starring:

1. Heart disease

2. Cancer

3. Neurodegenerative disease (think Alzheimer’s)

4. Type 2 diabetes

Whilst the research on longevity is still in its infancy - ;) - sleep has been linked with each of the Four Horseman.

So the question still remains - will good sleep help you outlive?

Unlike most personal experiments that I recommend you undertake for yourself, you can only perform a sleep-and-longevity experiment once.

So it makes sense to err on the side of caution, and look after your sleep.

And on that point, Dr Peter Attia and I agree - that you don’t have to kick your TV out of your bedroom … well he didn’t say it that way … but I have here in this Thirve Global article and this other WINK blog.

Cheers!

- Prof MG