Are you getting enough Zzzzzz for a Vibrant (& long) life?

Written by Liz Withyman
February 14, 2024

In this blog I’m taking a look at some science around Habit # 4 of my Coached Intermittent Fasting program: SLEEP! 

That most pleasant and fundamental bedrock of a Vibrant Life, which is hugely undervalued and under-prioritised in our society. 

Not getting enough sleep will not only undermine an Intermittent Fasting practice, it will undermine your health in every way. So if you want to do Intermittent Fasting, my advice would be to start with this: prioritise your sleep.

We are in a sleep deprivation epidemic

Many scientists say that we are in the middle of a sleep deprivation epidemic and that typically we are getting between 1 and 2 hours less sleep than people were 60 years ago. 


There are so many evening distractions in modern life including all the screens, which just didn’t exist for previous generations. 

And there’s also a sort of ‘sleep is a waste of your valuable time’ culture which makes it harder to have boundaries around sleep and make a stand for it. 

We need different amounts of sleep

Before I go on, I think it’s important to acknowledge that humans do vary in terms of the amount of sleep they need to be optimally healthy. 

Current science is showing that the old rule that everyone needs 8 hours a night is a myth. 

The natural range is actually more like 6-10 hours. 

The tired brain is good at fooling itself

However, having said that, as Oxford Professor of Circadian Neuroscience Russell Foster says, “you have to be careful, because the tired brain is very good at fooling itself that it’s ok. You need to be tough about assessing what your sleep needs are”. 

So, how do you work this out? Well, here are some sure signs that you are NOT getting enough sleep:

  • if you need an alarm clock to wake you up 
  • if you take a long time to come round in the morning 
  • if you crave caffeine first thing 
  • if you’re irritable and 
  • if you sleep much longer on days off or holidays…

…these are all signs that you are sleep-deprived. 

Another telling sign, highlighted by University of California Professor Matthew Walker, is: 

  • if you fall asleep extremely quickly, for example within 5 minutes, whether that’s during the day or in bed at night. 

7 – 9 hours is optimal for most people

Professor Foster stresses that we each have to define what our individual sleep needs are – there is no rule or number of hours, although studies show, and Professor Walker emphasises, that around 7-9 hours is optimal for most people and 6 hours or under is associated with disease. 

Many people don’t realise how sleep-deprived they actually are. 

Insomnia is a common problem

A second important point is that, whilst for some people, simply giving themselves a greater sleep opportunity by getting to bed earlier or sleeping a little later, will be enough for them to get good sleep, for others, insomnia can be a problem. 

The menopause often causes sleep disturbances even in women who never had a problem sleeping before. 

Health implications of sleep deprivation 

To give you an overview of how important sleep is: studies show that people who routinely don’t get enough sleep are more likely to get: 

  • cancer
  • stroke
  • Type 2 diabetes
  • heart disease
  • dementia

And studies show that the tired brain remembers negative experiences and forgets positive ones, so for anyone, being underslept affects your world view. 

And there’s mounting evidence that sleep deprivation is one of the biggest factors in being overweight, which becomes a vicious circle because in turn, being overweight affects sleep quality. 

So let’s add 

  • depression
  • anxiety
  • weight gain

Use this as permission to improve your sleep

If you have trouble sleeping, it’s not the intention of this blog to stress you about it, but I think you need the information about the consequences of sleep deprivation because it may motivate you to keep looking for solutions that work for you. 

Please use it as permission to do whatever you need to do in your life to improve your sleep if you’re not getting enough, because it’s a crucial factor for health and longevity. 

Why does short sleep affect health?

Our bodies and minds deal with stressors all day, and that creates cellular damage. 

During sleep, the body gets repaired, and our brains consolidate learning. 

We move through the different stages of sleep – deep, light, dream sleep – and have a number of cycles of this occurring every 90 minutes. 

When this doesn’t happen, it disrupts our circadian rhythm and with it, all sorts of processes in the body. 

Cancer study: The ‘U curve of sleep and longevity’

A 2002 Cancer Prevention study tracked a million people and identified a pattern known as the ‘U curve of sleep and longevity’ showing that people who consistently sleep too little (by which they meant 6 hours or less) are more likely to die early (of any cause) than those who get 7 hours of sleep a night. 

There is a sweet spot though because the study showed that those who slept more than 8.5 hours every night are also likely to die younger. 


Poor sleep is also specifically associated with dementia….a particular concern of mine because both my parents died of dementia.

A 2017 study found that healthy middle-aged adults who slept badly for just one night produced an abundance of beta amyloid plaques – one of the hallmarks of Alzheimer’s – and they found that a week of disrupted sleep also increased another protein responsible for the tangles that cause Alzheimer’s & other types of dementia. This does not mean that occasional poor sleep is something to worry about, since you will recover from this, but it does demonstrate the connection between sleep and this condition.

Another massive study published in April 2021 confirmed the association between lack of sleep and dementia. Nearly 8,000 people were followed for 25 years; there was a 30% higher dementia risk if peole slept 6 hours or less compared to those who slept seven hours a night. 


As well as the consequences for cancer and dementia, sleep deprivation is also strongly associated with being overweight. 

Basically, the less you sleep, the higher your blood glucose levels, so the more of the storage hormone, insulin, you’ll produce. 

Short sleep affects other hormones too, which will make you hungrier. 

Leptin is a hormone that makes you feel full…short sleep makes you produce less Leptin. 

Ghrelin is a hormone that makes you feel hungry (& crave carbohydrates). Short sleep makes you produce more ghrelin. 

So, when you aren’t getting enough sleep, you’ll be hungrier, and less likely to feel full when you’ve eaten. 

And, studies show that sleep deprivation makes you more likely to choose unhealthy food and less likely to exercise. 

So, if you’re convinced by all of that and you think you’re not getting enough sleep, what actions can you take to improve things?

What actions can you take to improve your sleep?

The following are suggestions from Professor Matthew Walker, renowned sleep scientist, author of ‘Why We sleep’:

1. Give yourself a non-negotiable sleep opportunity

His top piece of advice is to give yourself a minimum, non-negotiable 7/8 hour sleep opportunity by being in bed with the lights off, ready for sleep. We don’t generally fall asleep right away and it’s normal to wake up in the night so you need to make sure you give yourself longer with the conditions there for sleep than the number of hours you need.

2. Regular routine

Go to bed and get up at the same time every day, even weekends.

If you feel the need to sleep in late at the weekends to make up for lack of sleep during the week, this is a sure sign that you need to re-evaluate your weekday sleep patterns.

‘Social jetlag’ is associated with a number of adverse health outcomes, such as increased risk of obesity, metabolic syndrome and mental health issues.

3. Get the right light at the right time

Darkness in the evening

We need darkness in the evening to allow the release of the hormone melatonin. So Professor Walker recommends avoiding screens altogether in the evening. Professor Foster distinguishes between different types of screen use and suggests that if it doesn’t make you more alert it maybe ok, but what they absolutely agree on is that bright light for longer periods may affect sleep onset.

Daylight in the morning

And just as we need darkness in the evening, we also need daylight in the morning. Morning light triggers the production of melatonin, which is then released around 12 hours later…so getting morning light is THE best way to optimise your circadian rhythm.

So, take a 15-30 minute morning walk as soon as you can after you wake up (assuming it’s daylight….or consider a SAD lamp in the winter).

4. Get the temperature right

Keep your bedroom cool – your core temperature needs to drop by 2-3 degrees to sleep well.

It seems counterintuitive but taking a hot bath before bed makes your internal core temperature cool down because it causes blood circulation to go to your extremities

5. Avoid alcohol

Avoid alcohol in the evening.

It’s a ‘sedative’, so even if it seems to help you fall asleep, you’re actually just knocking your brain out, not giving it healthy sleep. It fragments your sleep, so you’ll wake up a lot more during the night even if you don’t realise it.

6. Caffeine

Only drink caffeine before noon.

We all react differently to caffeine, but on average, caffeine has a ‘half life’ of around 15 hours, and therefore a ‘quarter life’ of 10 hours, meaning that if you have a coffee at midday, it’s like drinking a quarter of that coffee at 10pm!

Some people can drink caffeine in the evening and still fall and even stay asleep, but your SLEEP when there is caffeine in your brain isn’t as deep. So when you wake up in the morning, you may not feel as refreshed.

7. Associate bed with sleep, not wakefulness

Don’t lie in bed awake. If you haven’t fallen asleep within 20 mins or it’s hard to get back to sleep if you wake up in the night, get up, go to another room and in dim light read a book. Go back to bed when you’re sleepy.

You want your brain to learn to associate bed with sleep, not wakefulness.

If you don’t want to get out of your nice, warm bed, you could meditate or do breathwork.

It’s tough to release old habits

It can be tough to release old habits and create new ones, but with sleep, it’s absolutely essential to having great health and a vibrant life!

If you want support with this or other habits for a vibrant life, get in touch!

Napping can help

However, having said all this, all is not lost if you can’t get all your sleep at night. 

People in the Blue Zones typically have a siesta in the hot part of the day, early afternoon, and stay up late, and do very well on it. That may not be practical in our society, but the main thing is that you get enough sleep, whenever that is. 

So if you can’t sleep well at night, can you find time to nap in the daytime? 

Studies show that a regular napping habit can lower your blood pressure and protects you against heart attacks. 

Man Utd and ‘human recovery periods’

Former mattress salesman Nick Littlehales became a sleep coach for Manchester United in their glory days in the 1990s at a time when sleep was not the hot topic it is today. 

It seems astonishing now but prior to this time athletes weren’t coached to prioritise sleep. 

So when the team’s manager Alex Ferguson hired a sleep coach, the Media had some fun at his expense, joking about how the coach tucked them up and read them bedtime stories! 

But in fact they were finding that the performance of the players was improving! 

He had them take what he called a ‘human recovery period’ around midday-early afternoon. 

They set up a dedicated room with loungers in it for the players so that they could sleep if they wanted to between their morning and afternoon training sessions. 

The result? 

The nappers performed better in the afternoon and were also more alert, and happier.

Power naps

So the message is, if you have trouble sleeping at night, try to get a little midday power nap… 

And maybe call it your ‘human recovery period’ instead of your ‘nap’, if you think that sounds a bit too middle aged…

Liz Withyman

Liz Withyman is an ICF-registered ACC (Associate Certified Coach) who trained with the Coaches Training Institute, the most rigorous and respected coach training in the industry. She runs her online Coached Intermittent Fasting Program 7 Habits for a Vibrant Life several times a year. 

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