How Important Is Sleep?
Quite simply, there is nothing in the body that sleep will not affect!
Let's put it this way: from an evolutionary perspective, the fact that we need to make ourselves so vulnerable to predation for an extended period of time every single day really highlights how important sleep must be for us!
Think about it, you are unconscious and completely defenceless for 8 hours every night. How easy does that make it for an animal of prey or even another human to take advantage and end your life? Ok so I'm possibly being a little dramatic here but you get my point, right?
Sleep is the most overlooked aspect when it comes to health and fitness. People tend to look at nutrition and training but not take into account the importance of sleep for:
- Muscle building
- Fat loss
- Mental clarity
- Training intensity
- Immune function
- Hormonal balance
You could be ticking all the boxes with your nutrition and training but if you are not getting adequate sleep then it will definitely hold you back.
Muscles grow when you're resting, not when you're training!
It's important to understand that when you are training, you are only creating the stimulus for change in the body. Putting the required stress on your body so that it adapts in the way that you want it to i.e. -build some muscle, lose some fat, increase strength or fitness. The actual adaptation to that stress happens when you are resting and obviously sleep is a key part of that.
When you are sleeping, the actual tissue growth occurs. Most systems in the body become very anabolic and new muscle is built, new bone is laid down, all of the hormonal cascades required to do so are switched on while you are sleeping so if you aren't sleeping enough then all of that will be hindered!
On top of that, neurotransmitters are being restocked in the brain whilst you are sleeping. These are responsible for mood, memory, focus, learning and attention span…. the list goes on!
A rather interesting fact is that studies have shown that decreased sleep (5.5 hours per night) can increase your respiratory exchange rate. What is this RER I hear you ask! Basically, it refers to how much of your total daily energy expenditure (the amount of energy you burn each day) comes from lean tissue vs fat mass. Fair to say that you would prefer to have more of it come from fat mass. If you have a higher RER then more of your daily energy is coming from your crucially important lean tissue (which you do not want to be losing).
However, what I see to be the biggest impact on people's body composition is the effect on hunger and cravings. I don't know about you but when I haven't had as much sleep as I normally get, I really crave carbs throughout the day. This is because lack of sleep will increase your ghrelin (hunger hormone) and decrease your leptin (satiety hormone). On top if that, there have been MANY studies showing that decreased sleep leads to disrupted blood sugar levels, overeating and cravings for high carb, high sugar foods. One study even showed an increase in BMR on subjects irrespective of their exercise and nutritional intake…. simply from lack of sleep!!!
I hope this helps clarify just how important sleep is to absolutely every aspect of your health.
Every single person should be aiming for 7-9 hours and this excludes no one. Even if you feel like you function well on less sleep, the chances are this is not actually the case and you have just adapted to operating at a subpar level.
*Disclaimer: Individual results vary based on agreed goals. Click here for details.