his week’s topic is something I’ve touched upon before in previous podcasts as it’s come up multiple times; in particular with regards to fat loss and stress reduction. But, sleep goes way beyond that in terms of how paramount proper sleep is to optimal health. And since 45% of the country is still chronically sleep deprived, it’s an even more relevant topic of conversation.
Today’s podcast we’re going to be talking about the top 5 reasons sleep is so important. But before we get into those reasons, let’s discuss why we sleep to begin with.
The question of why we sleep has been something scientists have pondered for centuries. There are a very small number of things that we cannot live without. Oxygen, food, water, and then there is sleep. That’s a small list, so sleep must be pretty important. If you forcibly keep an animal awake for a long enough time, it will die.
To be honest, we still don’t know the exact reasons why we sleep, because from an evolutionary perspective it makes absolutely zero sense. You’re way more likely to be killed or robbed while you’re asleep, so it creates a huge disadvantage to have to sleep. All we have at this point are a number of theories, and they’re all true to some degree but there isn’t really just one definitive answer on how sleep came to be wired into our systems.
One of the earliest theories of sleep was just that we fell asleep after we had eaten and taken care of all our duties and there was just nothing else to do. Another was that it was to conserve energy because food was scarce and if we were awake too long we’d run out of food. Obviously, those theories aren’t very popular now and we’ve moved on to better theories backed by science.
The restorative theory of sleep posits that sleep serves to “restore” what is lost in the body while we are awake. A lot of the restorative functions like muscle growth, tissue repair, protein synthesis, and growth hormone release occur mostly or sometimes exclusively while we’re asleep. In addition to that, while we’re awake the brain builds up what’s known as adenosine, which is a by-product of brain cell activity. When we have a big buildup of adenosine, that leads to us feeling tired. Side note, caffeine consumption counter-acts the tired inducing feeling of adenosine and keeps us alert. But, the only time we can clear this adenosine from our system is when we sleep.
So, we still don’t have a definitive answer as to WHY we sleep but at this point it’s an unanswerable question. We’re never going to be able to answer exactly why, but we know what happens when we don’t sleep and from that we can easily see why it’s so important that we do. So, after discussing some of those theories, let’s get into the top 5 science-based reasons of why sleep is so important.
Fat loss – Reason #1
Sleep and its relationship to fat loss. First and foremost, lack of sleep will lead to altered food choices due to the fact that it will cause an increase in the hormone ghrelin which is our hunger hormone. Ghrelin makes us hungry. It will also decrease the production of leptin, which is the hormone responsible for making us feel full. So, right off the bat we have more feelings of hunger and less feelings of fullness when we don’t sleep properly, so that right there is a recipe for disaster.
Lack of sleep will also make us more impulsive, so we become way more likely to make hasty and poor food choices. In addition to that, when we don’t get enough sleep we’re obviously going to have less energy so the next day we don’t move as much and we don’t burn as many calories.
And finally, in regards to fat loss, lack of sleep leads to decreased cellular resiliency and also increases cortisol which will cause fat storage and more specifically fat storage around the abdominal area.
Muscle gain – Reason #2
Sleep and its relationship to muscle gain.
So, in addition to cortisol causing you to store fat around the abdomen, increased cortisol will also lead to muscle atrophy and will also lower testosterone which is vital for proper muscle growth. The increased cortisol will also lead to insulin resistance and without proper insulin sensitivity its next to impossible to build muscle in addition to numerous other health maladies that accompany insulin insensitivity.
Another factor that makes sleep vital for muscle growth is that during sleep we secrete growth hormone. This hormone production typically happens during deep sleep, also known as stage 3 of non-REM sleep. Growth hormone also stimulates insulin like growth factor, which helps shuttle carbohydrates into our muscle cells to repair them and allow our body to recover from our workouts.
Immune System - Reason #3
The 3rd reason sleep is so important is because of its impact on our immune systems. One study showed that participants who got less than 7 hours of sleep were nearly 3 times more likely to develop a cold then participants who slept 8 hours or more.
Sleep improves the function of the very cells of our immune system in particular T-Cells. These T-cells are super important for fighting off viruses and also preventing diseases from forming and have been linked to reduction in cancer rates.
Researchers have also discovered that while we sleep, different components of the immune system interact and essentially speak with each other to help improve our immune system memory. This means sleep allows our immune system to remember how to recognize and react to different antigens in order to have a quicker and more efficient response the next time it encounters said antigen. So, when we’re sleeping the immune system, which is like our internal army, gets together and lays out a plan of defense for our bodies. Pretty cool stuff.
Inflammation - Reason #4
Reason #4, sleep also plays a very important role in inflammation. However, just as too little sleep will trigger inflammation, so will too much sleep. The reason for this is that inflammation is heavily tied into our circadian rhythm. When our rhythm is off, whether it’s from too much or too little sleep, we’re more prone to inflammation.
A 2016 review of more than 70 studies revealed that in addition to lack of sleep, too much sleep also raises those key markers of inflammation like C-Reactive Protein. On the flip side, another study showed that just one poor night of sleep will increase other markers of inflammation like interleukin-6 and tumor necrosis factor.
That is why it’s so important to keep a consistent sleep schedule in terms of what time you go to bed and what time you wake up. This way we can keep our circadian rhythm in check and therefore inflammation in check. Ideal amounts of sleep will vary person to person but it seems, generally speaking, we should shoot for between 7-9 hours.
Longevity - Reason #5
Last but not least, sleep has a huge impact on our lifespan. One huge factor in determining life span is what’s known as telomeres. Telomeres are DNA-protein structures that form protective caps at the end of our chromosomes. Their job is to stop the ends of chromosomes from fraying or sticking to each other, much like the plastic caps at the end of our shoe laces. Reduced length of these telomeres has been associated with a number of degenerative diseases in humans, and we’re now starting to learn their role when it comes to aging. We’ve seen in animals’ studies that the longer the telomere, the longer the life span of that animal.
What helps lengthen our telomeres? Sleep. People who get roughly 7 or more hours of sleep per night tend to have longer telomeres. This is true in the elderly, adults, even children! People who get 5 or less have much shorter telomeres.
In addition to increasing telomere length, lack of sleep has been associated with all the top diseases like heart disease, diabetes, and cancer. And as I mentioned at the top, the common denominator of all those diseases ties back to stress. So, sleep more. Stress less. Live longer!
Alright guys, those are just 5 reasons why we should strive to optimize our sleep, there’s plenty more but if those aren’t enough then I don’t know why you’re even listening to this podcast to begin with!