We might think the following is obvious, if we become 75 years old, we will have spent 25 years sleeping. Well, we sleep a little less nowadays since it seems that our hyperactive society is taking its toll on sleep duration. We sleep at least one hour less than our grandparents did. Sleep is important, we can derive this from the fact that although we are vulnerable and helpless during sleep, we still spent 7-8 hours a day on it. So there must be an evolutionary importance to sleep. If it wasn’t so important we could do with less.

For me sleep is important to counterbalance the mental and physical load, the wear-and-tear during daytime. Sleep is for repair, recovery, replenishment, regeneration, and relaxation. To unload and recharge the psychological systems that we use during daytime.

Research shows that sleep is important for:

  1. “Cleaning” the brain with help of the glymphatic system
  2. The functioning of memory storage
  3. Balancing the autonomic nervous system, more parasympathetic dominance during sleep and sympathetic during daytime
  4. Secretion of hormones, creating an anabolic state thus repairing cells and tissues, like growth hormone, melatonin, orexin

Modern society and its improvements allow us and push us do more things during daytime. Artificial light, TV, computers, laptops and smartphones challenge us to create longer days and shorter nights with less sleep. But we all can guess what will happen if at the one hand we sleep one hour less than necessary, but work or play one hour more. This goes both ways, creating a chronic imbalance.

Last night you slept 5% less than necessary in order to cope with today, you start the day with 95% energy, the day is long and exhaustive and you work one hour more than normal. So your sleep tonight is also going to be 5% too short, tomorrow morning you wake up with only a 90% energy level.

During holidays, lying at the swimming pool or on the beach, that 10% might not make a difference, but if you need to perform at a high or the highest level, and your attention is important, this might make a difference. Think about elite sports or air traffic controllers, surgeons, pilots, truck drivers, etc. You will simply have a higher probability of errors and at least setting up for submaximal performance.

Since the effects of lack of sleep are subtle and hard to detect, it is easy to overlook and ignore. Sleep loss has become a problem and therefore a commodity for sleep coaches (!), sleep trackers, sleeping aids, etc. I am not going to repeat the tens of rules for proper sleep, you already know them very well and you can find them everywhere. It is common sense which is not that common anymore. But know that sleep is not merely a waste of time that could be used better by looking at social media. Just get your sleep, it will help you to perform and maintain your health, and yes it is a marginal but might make a difference.

For further reading:

  • Keferstein, G: Praxisbuch Schlafoptimiering (in German); Pflaum Verlag, 2020.
  • Rasch, B;  Born, J: About sleep’s role in memory;  Physiol Rev 93, 2013, pg. 681–766
  • Dew, M.A: : Healthy Older Adults’ Sleep Predicts All-Cause Mortality at 4 to 19 Years of Follow-Up; Psychosomatic Medicine 65, 2003, pg. 63-73
  • Cirelli, C; Tononi, G: Is Sleep Essential? ; Plos Biology August 2008, Volume 6,  Issue 8, e216
  • Shochat, T: Impact of lifestyle and technology developments on sleep; Nature and Science of Sleep 2012, 4, pg. 9–31
  • Karl Hecht; Schlaf, Gesundheit, Leistungsfaehigkeit; Springe , 1992
  • Diekelmann, S: Sleep for cognitive enhancement; Frontiers in Systems Neuroscience 2014, Vol.8,Article 46, 2
  • Akerstedt, T.A; Nilsson, P.A: Sleep as restitution: an introduction;   Journal of Internal Medicine 2003; 254, pg. 6–12
  • Irwin, M.R: Why Sleep Is Important for Health: A Psychoneuroimmunology Perspective;  Ann. Rev. Psychol. 2015, 66, pg. 143-172
  • Aalling-Jesseern, N; Finmann, A.S, The Glymphatic System: A Beginner’s Guide;  Neurochem. Res. 2015, 40, pg. 2583–2599
  • Walker, M.P; Stickgold, R: It’s Practice, with Sleep, that Makes Perfect: Implications of Sleep-Dependent Learning and Plasticity for Skill Performance; Clin. Sports Med. 24, 2005, pg. 301– 317
  • Milewski, M.D; Skagg, D.L. et al: Chronic Lack of Sleep is Associated With Increased Sports Injuries in Adolescent Athletes; J. Pediatr.Orthop. 2014, 34, pg.129–133
  • Datilo, M; Antunes, H.K.M. et al: Sleep and muscle recovery: Endocrinological and molecular basis for a new and promising hypothesis; Medical Hypotheses 77, 2011, pg. 220–222
  • Halston, S.L; Juliff, L.E: Sleep, sport, and the brain; Progress in Brain Research;  Volume 234, 2017, pg. 13-31

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