Why The Lion Sleeps Tonight

Ah, sleep. Hardly an exciting topic in the health and fitness world, but one we need to pay attention to.


The truth is, many people sacrifice their sleep in favor of having more time for work and leisure. But sleep deprivation can wreak havoc on our health, make us lose focus, and impact our fitness outcomes.


In this guide, we’ll explore the significance of sleep for fitness and what that means for you. Let’s dive in.


But First: What is Sleep Debt?


Sleep debt is quite similar to financial obligations. Think about it this way:


As a person spends more money than they earn, debt accumulates. The longer they live like that, the greater the debt becomes, and the more difficult it gets to pay it off.


Sleep debt is the same. The more we sleep less than we should, the more sleep debt we accumulate, and the greater our sleep deprivation becomes. Research suggests that sleeping for less than six hours per night for two weeks has the same neurological impact as staying up for 48 hours straight.


What’s worse about sleep debt is that most people think they are doing fine and never realize their performance is declining. In their eyes, they are doing well and can get away with less sleep. In everyone else’s eye, they are performing worse on every cognitive and physical task.


Sleep’s Impact on Fat Loss


Sleep is crucial for fat loss on several fronts. As it relates to:

  • Hunger and impulse control
  • Metabolism and the body’s ability to burn fat
  • Motivation and energy levels to do different things


Let’s take a look at each of these.


  1. Hunger and impulse control


Sleep has a profound impact on frontal lobe activity. This is the part of the brain responsible for decision-making, impulse control, and other related behaviors. The problem is, sleep deprivation hinders frontal lobe activity, which makes us more impulsive and less able to control our urges.


This leads to poor decisions, especially as it relates to our nutrition. We are less able to control our food-related impulses and often find ourselves eating unhealthy foods and seeking instant gratification.


Sleep deprivation also appears to raise levels of the hunger hormone ghrelin. As a result, we feel hungrier throughout the day and experience more cravings for salty, sugary, and fatty foods.


  1. Metabolism and the body’s ability to burn fat


A fascinating study from 2010 found something interesting about sleep and our ability to burn fat. In that paper, subjects got to sleep for 8.5 or 5.5 hours per night. They followed a special weight loss diet in both scenarios.


When they got to sleep for 8.5 hours, half of the subjects’ weight loss came from actual fat. In contrast, when they only got to spend 5.5 hours in bed, only a fifth of their weight loss came from fat.


Everything else was the same in both conditions, but their sleep. This alone tells us how vital it is to sleep if we want to achieve optimal fat loss.


  1. Motivation and energy levels to do different things


There is no other way to put it:


The less we sleep, the more tired we are, and the less we want to move around and do things. This results in lower activity, a higher risk of skipping workouts, and fewer calories burned.


How Does Sleep Impact Our Ability to Build Muscle?


That’s right - we are not done yet because sleep deprivation impacts more than our ability to burn fat and get lean. As it turns out, not getting enough sleep can directly impact our ability to build muscle and strength. Let’s review.


  1. The impact on hormones that play essential muscle-building roles


Sleep deprivation decreases levels of two essential hormones for muscle growth - testosterone and IGF-1. As you’ve probably heard before, testosterone is the most powerful anabolic hormone in the body. It influences muscle growth, bone health, energy levels, strength, and much more. Having lower levels hinders our ability to train hard, recover well, and build muscle mass. 


Most notably, testosterone increases muscle protein synthesis and inhibits specific proteins that block the mTOR pathway. Not having enough of it makes these effects impossible.


  1. Sleep deprivation and the stress hormone cortisol


You’ve heard of cortisol before, haven’t you? Primarily known as the stress hormone, cortisol plays numerous vital roles in the body. The problem occurs when cortisol becomes chronically elevated, which is often the result of sleep deprivation. This leads to:

  • Lower protein synthesis
  • Higher protein breakdown
  • Water retention
  • Cardiovascular issues


Cortisol oversees catabolism (breakdown) in the body, so it’s in our best interest to keep it in a healthy range by managing stress and sleeping enough.


  1. Sleep’s effects on our energy levels, motivation, and general well-being


The lack of sleep leads to fatigue, brain fog, and a lack of motivation. This is more of an acute effect but one that doesn’t go away from prolonged sleep deprivation. Yes, not getting enough sleep is one of the few things your body can’t adapt to.


These adverse effects persist until we begin to sleep more and pay off our sleep debt. General fatigue makes us less likely to move around during the day and can hinder our gym performance. Brain fog, an inability to focus, and a lack of motivation are also alarming for workout performance. If you do make it to the gym, you won’t be able to concentrate and train as hard. 




Sleep is something we often sacrifice in favor of other, seemingly more important things like work or catching an extra episode of our favorite show. And the truth is, not getting enough sleep occasionally is not the end of the world. It won’t stop fat loss and prevent you from building muscle.


But the keyword here is occasionally. Chronic sleep deprivation wreaks havoc on our health. It makes us tired, saps our motivation, and hinders our abilities to control our impulses. It also has direct physiological effects on our abilities to build muscle and lose fat optimally.


So, what can we do about it? Well, sleep for seven to nine hours per night.


Wake up refreshed and throw on some Apex Apparel to crush your workout!  Available at: www.apex-fitness.ca


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