By Drew Linge, Pre-Med Student. Ocyon Regenerative Intern

Sleep is one of the most vital aspects when it comes to recovering from a Regenexx procedure. When we sleep we move through sleep cycles, which last approximately 90 minutes each. With each cycle we move through 4 stages of sleep and an additional stage known as rapid-eye movement (REM) sleep. During different times of the sleep-wake cycle, there are 3 main waves emitted: Alpha, Theta and Delta. When you’re awake and active, your brain is emitting Alpha waves; these waves have the highest frequency.

As you fall asleep you enter Stage 1 which quickly turns into Stage 2 sleep. When a person in Stage 1 or 2 is awoken, they will usually say that they never fell asleep at all. During these stages the brain is still very active, and it is easy to wake someone who is currently in Stage 1 or 2. However, your brain is now emitting Theta waves which have a slightly lower frequency than Alpha waves. Theta waves can also be seen when a person is awake, but that person must be in a restful, relaxed state.

Stages 3 and 4 are known as deep sleep. This is where it becomes difficult to rouse someone. The brain is mainly emitting Delta waves now which have the lowest frequency. After Stage 4 your body moves backwards through the stages until it hits Stage 1 again, from here you move into REM sleep. During REM sleep your eyes rapidly twitch around, hence the name. REM sleep is fascinating as our brain waves resemble a brain that is awake but muscle activity in the body is prohibited. This phenomenon explains why REM sleep is where almost all our dreaming occurs.

As we prepare for sleep, there are key hormonal changes that set the stage for bodily growth and repair. Cortisol, a stress hormone, is almost at its lowest point right as we fall asleep. Shortly after the onset of sleep we see cortisol levels at their lowest point, from here cortisol levels will rise as we sleep and will peak shortly after we awaken (Figure 1). Throughout the day our cortisol levels decrease until they reach that low point before bed and the cycle repeats. This repeating function allows for proper release of beneficial hormones during sleep. These beneficial hormones are known as Growth Hormone (GH) and Thyroid Stimulating Hormone (TSH). When cortisol levels increase during the day due to stress it can throw the body out of tune. An increased cortisol level experienced before bedtime can cause sleeping problems, which then directly impacts your body’s ability to release GH and TSH for growth and repair.

GH is crucial to recovery and growth as it directly stimulates growth in many tissues including: muscles, cartilage, liver and bone. GH levels sharply rise directly after the onset of sleep (Van Cauter and Plat 1996), which can also be seen in Figure 1. GH is also released during stages 3 and 4 of sleep (Van Cauter and Plat 1996) but is less intense than the initial burst seen right as we fall asleep. As cortisol levels increase throughout sleep it inhibits the release of GH (Sartin et al. 1994) and less GH is released as sleep progresses. Fortunately, cortisol is inhibited during stages 3 and 4 so that some GH can be released (Van Cauter et al. 2008).  

TSH acts on the thyroid gland to release hormones T3 and T4. TSH increases before sleep, peaks right before the onset of sleep and decreases until bedtime the next day (Figure 1). Decreasing cortisol levels during daytime allow for TSH to increase before bedtime. Hormones T3 and T4 are responsible for proper bodily function and for growth and development, they even synergize with GH to promote better growth (Bowen 2010).

A good night’s sleep, anywhere from 7-10 hours, allows the body to go through more sleep cycles than if it had only slept 4-5 hours. More hours of sleep equates to more sleep cycles, ultimately leading to more hormonal release and more healing accomplished.


  1. Van Cauter and L. Plat, “Physiology of growth hormone secretion during sleep,” The Journal of Pediatrics, vol. 128, no. 5, pp. S32–S37, 1996. 

Eve Van Cauter, Karine Spiegel, Esra Tasali, Rachel Leproult, “Metabolic consequences of sleep and sleep loss”, Sleep Medicine, Volume 9, Supplement 1, 2008, Pages S23-S28

J L Sartin, R J Kemppainen, E S Coleman, B Steele, and J C Williams, “Cortisol inhibition of growth hormone-releasing hormone-stimulated growth hormone release from cultured sheep pituitary cellsJ Endocrinol 141, 1994, 517-525

Bowen, R. (2010-07-24). “Physiologic Effects of Thyroid Hormones”. Colorado State University. Retrieved 2018-06-29.

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