Proactive Icon
Proactive Sleep

Bodily Cycles

The human body has cyclical ebbs and flows much like the ocean tide. As a result, there are better and worse times to wake up, fall asleep, do work, take a nap, etc. Also like the tide, with the right information, these patterns can be predicted. This requires understanding sleep stages and the homeostatic and circadian components of our bodily cycles.

Sleep is Dynamic

Sleep is made of generally three stages:

  1. Light Sleep
  2. Deep Sleep
  3. REM sleep
These recur somewhat predictably in about one to two hour intervals following the pattern:

light sleep → deep sleep →
light sleep → REM

The two major factors that affect sleep / wake patterns are the homeostatic and circadian components.

The Stages of Sleep

Deep sleep contrasts greatly with the brainwaves that occur in REM, light sleep, and waking life. During deep sleep, the frequency of brainwaves decreases and the wavelength increases, as large swaths of neurons fire on and off in a long oscillating manner. Since this is very different from brainwaves that occur when you are awake, waking during deep sleep increases grogginess and disorientation [1][2].

The Homeostatic Component

The Homeostatic Component is the accumulated pressure to fall asleep the longer that you are awake. When you are sleep deprived, the body compensates by increased need to fall asleep and increased amount and intensity of deep sleep. Since deep sleep dissipates as sleep need decreases, sleep cycles get gradually shorter if you sleep for a longer amount of time and are less sleep deprived.

The Circadian Component operates in a 24 hour cycle and affects various biological processes throughout the day, such as body temperature, blood pressure, and sleepiness. You may find it particularly difficult to wake up at about 2:00 am to 4:00 am and that you are usually drowsy after lunch, at around 2:00 pm to 4:00 pm [3][4][5]. This is due to the circadian component, which is usually at its lowest point during these times. Exposure to bright light in the morning is known to affect this aspect of the sleep / wake cycle.

1) Kuboyama, T., Hori, A., Takayuki, S., Mikami, T., Yamaki, T., Ueda, S. (1997). Changes in Cerebral blood flow velocity in healthy young men during overnight sleep and while awake. Electroencephalography and clinical Neurophysiology 102, 125.

2) Tassi, P., Bonnefond, A., Engasser, O., Hoeft, A., Eschenlauer, R., Muzet, A. (2006). EEG Spectral power and cognitive performance during sleep inertia: The effect of normal Sleep duration and partial sleep deprivation. Physiology & Behavior 87, 177.

3) Dinges, D. F., Orne, M. T., & Orne, E. C. (1985). Assessing performance upon abrupt awakening from naps during quasi-continuous operations. Behavior Research Methods, Instruments, & Computers, 17, 1, 37-45.

4) Takahashi, M., Fukuda, H., Arito, H. (1998). Brief naps during post-lunch rest: effects on Alertness, performance, and autonomic balance. Eur J Appl Physiol 78, 83-98.

5) Scheef, F., Shea, T., Hilton, M., and Shea, S. (2008). An endogenous circadian rhythm in sleep inertia results in greatest cognitive impairment upon awakening during the biological night. Journal of Biological Rhythms 23, 4, 353-361.

Proactive Sleep ™ is a Proactive Life product.
Twitter  |  Support  |  Terms  |  Privacy