Sleep, rest and recovery plays a massive part in a healthier lifestyle. The stress hormone, cortisol can wreck havoc in our bodies if it’s not looked after properly. On top of that, if we don’t get enough sleep, at the right time of night, then we’re adding fuel to the fire which again, will stir our cortisol monster. To understand why this happens we need to learn about our circadian clock.

Circadian clock

Way before the British invented the grandfather clock and the Swiss invented the wristwatch, mother-nature beat them to it by creating the bodies circadian (pronounced sir-kay-dian) clock. It works by keeping time primarily from the rising and setting of the sun, which activates a hormone in our body called melatonin.

The circadian cycle wasn’t created just for us humans. Nature also created the circadian cycle (often referred to as the biological rhythm) for every living thing on the planet; from animals to fish, from plants to microbes. Understanding the cycle is extremely important to our health, so much so that in the 1980’s a whole new field of science was created to study it – chronobiology.

For those of us who live a large distance from the equator, our bodies have to adapt to huge swings in the hours of sunlight that we receive throughout different seasons. In the UK during the darkest winter days, we get as little as eight hours sunlight, but in the middle of the summer we receive a whopping sixteen. With our circadian clock being regulated by sunlight, it’s a good thing that the change happens subtly, with sunrise and sunset changing by approximately just one minute each day.

Our 24 hour clock and how it works

Midnight – To make sure we feel tired, the melatonin production in our bodies reaches its peak. The thyrod gets to work and tells the mitochondia in our cells to burn energy to keep our inactive body’s warm. By allowing our bodies to sleep properly we’re also allowing the process of weight loss to happen, too.

1am – Melatonin slows down our brain activity so that we can process what we have learnt in the day and this in turn forms long term memories.

2am – This is our deepest sleep point, where the body starts to enter repair mode.

4am – We are at our most relaxed here and both our nuerological and immune systems are hard at work.

5am – Because it takes 5 or 6 hours of sleep for our body to reach its lowest temperature, it’s important to make sure we get no less than 7 hours sleep.

6am – Our cortisol and blood pressure level rises in an attempt to wake up the brain and mobilise our muscles.

7am – The body stops producing our sleep hormone melatonin at this point and instead switches on our hunger hormone, ghrelin.

8am – Our bowels become active and should stir movement from the food eaten the day before.

9am – Our testosterone levels are at their secretion for the day.

10am – The most alert we will be all day.

2pm – Height of coordination (so we could track and hunt animals after the midday sun).

3pm – Fastest reaction times (so that we could catch said animals).

5pm – Maximum muscle strength and cardiovasular efficiency (in case we didn’t catch animal first time).

6pm – Highest Blood Pressure of the day. As long as you are on a low carb diet, in order to stop you eating too much, your leptin levels will continue to rise until bedtime.

7pm – Peak time of body temperature.

9pm – The body starts to produce melatonin to tell us we are tired.

11pm – Gastrointestinal starts to work so that we are not going to the toilet all night.

One thing to remember is that sunlight is the one thing that keeps our body in sync. The above chart of times is based on the sun rising at 6am and then setting at 6pm, as it does mid spring and autumn in the UK or pretty much all year round near the equator. At other times of the year, as the hours of sunlight move backwards and forwards by only a minute each day, our circadian clock is able to fairly and reliably reset itself. However, problems arise when we travel abroad or work nightshifts as our bodies need to adjust to the bizarre time differences – something which we really struggle with.

Primal Sleep: When we sleep, our brain begins its magic show, collating, storing and making sense of what we learnt during the day.

What happens to our body when we sleep?

  • The body goes into repair mode and increases our growth hormones
  • The brain assembles the jigsaw puzzle of knowledge that we learnt during the day
  • The brain takes the daily learning’s and files them neatly into the brains filing cabinets so that we can more easily retrieve and recalled it in future
  • The liver without having to deal with incoming food (its difficult to eat when you are a sleep), gets to work detoxifying our body
  • The body increases the production of testosterone

What happens when we don’t get enough sleep?

  • Knowledge and memories from the day’s activities become scrambled
  • The body struggles to regulate our body temperature and becomes particularly inefficient at dealing with extreme cold or heat
  • The body creates an excess of cortisol and we become easily stressed. Have you noticed how short tempered we become after a poor nights sleep? It’s not our fault that we become irritable and ratty, its an excess of the hormone cortisol
  • Our immune system begins to fail
  • Insulin struggles to regulate blood sugar levels and a lack of sleep can lead to Diabetes type 2
  • Leptin and ghrelin hormones don’t function properly leading to overeating
  • Our body can lose control of its fight with inflammation

Many people, including myself, limit how much they sleep for many reasons. For twenty-six years, I limited the amount of hours I slept because I thought it made me a better person, a smarter businessman and because I believed it gave me more time to achieve things. However, it turned out that while I had a feeling of self-righteousness, getting out of bed at the crack of dawn, hours before most of the population even drew their curtains, I was actually weakening my body by stopping my muscles from growing properly. I was stupid enough to believe that surviving on limited sleep was sufficient enough but in fact, I was not allowing my brain to properly organise itself from what I was learning and achieving.

So how much sleep do we really need?

It’s quite obvious that all our bodies are completely different in many ways. However, the more active we are, the more sleep we need. I personally get around 7 to 8 hours worth of sleep during weekdays and when it comes to the weekend I get as much as 10 hours a night.

But what do the experts recommend? The National Sleep Foundation of America assembled eighteen leading scientists and researchers and recently gave them the task to bring up-to-date their official recommendations. As of June 2017, this is what they suggest:

In the UK we also have similar guidelines and as it is so well researched, I personally like to refer to the above.

Whilst it might be true that government leader, Margret Thatcher got by on 4 hours sleep each day, was it actually good for her health? Absolutely not! Researchers at the University of California in San Francisco, discovered that 3% of people have a gene that enables them to perform well on just six hours sleep per night. But for the other 97% of us, in order to live a healthy, happy and long life, we need to follow the above recommendations.

At the end of the day, it’s extremely important to take into consideration just how much you’re really looking after your body. Your body is a working machine and in order for it to run properly you must maintain it well. This means you need to rest (in order to let your muscles fully recover), get enough sleep (at time right time) and also listen to your body when it’s silently telling you to slow down.

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Find out more about our circadian clock and why the cycle is extremely important to our health, so much so that in the 1980’s a whole new field of science was created to study it – chronobiology!