Sleep

Sleep is one of the most important and underrated aspects of strength training recovery. Sleep is widely overlooked in the strength world, and only in recent years has caught the attention of lifters across the globe.

Great, but what is sleep anyway, and how does it affect your strength training?

What is sleep?

According to the literature, sleep doesn’t have one simple definition. We might understand it as a state of unconsciousness, but the scientific community defines sleep a little more broadly since sleep itself varies from species to species. 

Sleep can be defined as a “loss of locomotion, maintaining distinct posture, enhanced arousal threshold to environmental stimuli, rapid reversibility, preference for specific environmental location, and homeostatic rebound to sleep deprivation.” (7)

Stages of sleep

You have likely heard someone talk about REM sleep (or Rapid Eye Movement), but what you might not have heard about was its counterpart, NREM sleep (Non Rapid Eye Movement).

REM Sleep 

Using electrical signals, scientists can monitor out sleep and therefore create graphs, patterns and characteristics about each phase of sleep. During REM sleep, the electrical signals in our brains are similar to that of being awake. However, when we are in REM sleep, our bodies actively suppress movement. For example, if you are having a dream that you are running, your brain is signalling your legs to RUN, but we both know you aren’t actually running. Your brain has other mechanisms in place to inhibit your legs from moving. 

During REM sleep, as stated above, you dream. Your dreams are likely going to be very illogical or bizarre and almost seem life-like. These dreams can range from totally out-in-left-field dreams to very real, almost nightmare-ish dreams. And, much like the name suggests, your eye rapid move during REM sleep. They dart back and forth and up and down beneath your eyelids like you’re looking at something in your dreams…similar to being awake.

REM sleep is very different than its counterpart, NREM sleep.

NREM Sleep

The electrical signals of NREM sleep are vastly different than REM sleep. In fact, one might say they are polar opposites. While REM sleep is distantly similar to being awake, NREM sleep is not. Dreams in NREM sleep are bland or logical, and movement is not inhibited. During NREM sleep, your body can and does move involuntary. Now how much it moves varies person to person, but movement does occur. 

NREM sleep is divided into four stages: N1, N2, N3, and N4. The first stage, N1, is the transition between awake and asleep. It’s the point in your sleep when you are easily woken by a sudden noise or unfamiliar sound. Each stage requires more and more stimuli to wake you up, so by the time you reach N4, you’re in a fairly deep sleep. (1, 2)

Learning and Memory

When we sleep, we learn. Crazy right? When we are consciously doing nothing, our subconscious is going a million miles and hour. During REM-rish sleep, our memory for tasks and skill that are considered “knowing how” tasks (walking, talking, playing and instrument…lifting technique) increases. Whereas NREM sleep is important for our memory of “knowing that” tasks (like studying for a test). However, as we normally have to do with science, we must take these with a grain of salt. Other studies have not been able to directly verify the above information. Therefore REM sleep may or may not be a vital function of memory…crazy right? (3)

Sleep & The Body

There have been several theories postulated for the function of sleep:

1. 1. To restore the immune and endocrine (hormone) systems.
   2. Neurometabolic theory – Recovering the energy lost by the nervous system and metabolism during waking hours 
   3. Cognitive development – Learning and memory

But how to REM and NREM play a role in these theories? NREM appears to play a role in energy recovery and restoration of the endocrine system. During NREM sleep, there is a reduction in your body’s oxygen consumption, thus lowering the metabolic rate and therefore allowing your body to recoop some of its lost energy (4, 5). Additionally, NREM has been shown to be the body’s stimulus for anabolic hormones (muscle growth hormones) that increase protein synthesis and increase your body’s use of stored fat to provide energy while sleeping (rather than breaking down muscles for energy) (6). 

So to sum that all up, during NREM you take in less oxygen because you are using less energy. This allows your body to build-up its energy stores for when you’re awake. Additionally, when you are in NREM, your body uses stored fat as energy AND increases protein synthesis…so to say that NREM is important would be an understatement.

But what about REM? REM is essential for cognitive development (learning and memory). REM sleep is critical for establishing brain connections since brain activity in REM sleep is similar to that of being awake (6). 

Sleep & Athletic Performance

For the average person, the National Sleep Foundation recommends getting 7-9hrs of sleep per night. But for athletes, scientists recommend athletes get 9-10hrs of sleep per night. That is 1-3hrs more than the average person per night!

But think about it, the amount of damage and energy loss the average person accumulates during the day is far less than an athlete might accrue, especially if they are strength training as well. As athletes, we have 2-3hrs a day that we brutally beat-down our bodies, so we need that extra to recover our energy, heal our bodies, and heal our minds (as cheesy as that sounds).

There is an excellent review all about sleep and athletic performance. You can find that article HERE. 

Summary

As a female strength athlete, it is essential that we get 9-10hrs of sleep per night. If we don’t, we are risking putting out bodies in a state of under-recovery and energy deprivation (not to mention all the cognitive consequences). So do you and your body a favor, sleep MORE!! 

Ready to take your nutrition to the next level? Check out our Eat for Strength course HERE.

Want to learn more about sleep? Listen to Episode 105 of Empowered by Iron podcast. 

References

1. https://link.springer.com/article/10.1007%2Fs40279-014-0260-0
2. https://www.sciencedirect.com/science/article/pii/S0896627317300387?via%3Dihub
3. https://www.jneurosci.org/content/37/3/457.long
4. https://www.annualreviews.org/doi/abs/10.1146/annurev.me.27.020176.001301?journalCode=med
5. https://science.sciencemag.org/content/150/3703/1621
6. https://www.ncbi.nlm.nih.gov/pubmed/4307378?dopt=Abstract
7. https://www.sciencedirect.com/science/article/pii/S0079612317300560?via%3Dihub