Sleep Deprivation: Causes, Effects, and Strategies to Address
by Joseph Giandonato, MBA, MS, CSCS
Faculty
World Instructor Training Schools
According to Cheung and Ainsle, sleep deprivation is among the most insidious health issues facing modern society (2022). Sleep deprivation is characterized by a disruption in sleep which may encompass a “complete absence of normal sleep at normal times, or abnormally long periods of wakefulness” (Cheung & Ainsle, 2022, p. 216). Previous research has implicated sleep deprivation as a risk factor of multiple cardiovascular and metabolic diseases, while contributing to immunosuppression, systemic inflammation, and potentially impacting in-vivo environments as sleep deprivation during the third trimester as it has been shown to increase risk of hypertension among offspring (Liew & Aung, 2021). Relatedly, correlations between sleep deprivation among males and females has been shown to adversely affect reproductive health (Cho & Duffy, 2019). Longitudinal data has shown that sleep deprived individuals suffering from cardiovascular, metabolic, or immune disorders have poorer outcomes associated with their conditions (Gabarino, Lanteri, Bragazzi, Magnavita, & Scoditti, 2021). But the effects of chronic sleep deprivation span further than the tangible decrements in physical health.
A meta-analysis of 64 studies revealed a strong correlation between sleep deprivation and mood, emotion, and emotional regulation throughout the lifespan (Tomaso, Johnson, & Nelson, 2021) corroborating the findings of an antecedent meta-analysis which suggested a link between sleep deprivation and anxiety (Cox & Olatunju, 2020). Both acute and chronic sleep deprivation have been shown to adversely impair endurance performance, mean and peak power outputs during a Wingate Test, limit strength performance, accuracy, and reaction time, while eliciting decreased time to exhaustion, increased perceived exertion, and altering muscle glycogen stores (Watson, 2017). Further, reduced sleep duration resulting in a state of sleep deprivation has been shown to adversely impact neurocognitive functioning with reports of elevated confusion and mood disturbances, while decreasing focus and vigor (Cheung & Ainsle, 2022). Further, sleep deprivation can be detrimental to cognitive and psychomotor learning, as sleep is critical to memory consolidation. It is theorized that the former is most affected by sleep deprivation since memory consolidation, a process of synaptic plasticity encompassing the conversion of temporary labile memories in the hippocampus to imprinted ones amid regions of the neocortex.
Sleep deprivation can also impede recovery from exercise and potentiate elevated injury risk. A study evaluating the effect of sleep deprivation on muscle recovery reported that protein synthesis was reduced among the combined sleep deprivation and exercise cohort and elevated creatine phosphokinase levels and reduced clearance rates (Yang et al., 2019). In fact, just one night of sleep deprivation resulted in significant alterations of ultra-sensitive C-reactive protein and myoglobin levels among exercise study participants (Mejri et. al., 2016). C-reactive protein concentrations have been shown to adversely affect cardiovascular health while increasing incidence of cardiac events. However, the increase noted in the study was only temporary and ostensibly attributable to acute inflammation and endothelial dysfunction resulting from sleep deprivation. Impairments in reaction times and neurotransmission are associated with sleep deprivation which plausibly explains why higher incidences of injury have been reported in sports participation and bicycle accidents (Milewski, 2014; Kim, Sim, Kim, & Choi, 2015).
Potential Causes of Sleep Deprivation
Disruptions in sleep can be instigated by psychological stress, injury, neurological conditions, and regular use or abuse or recent cessation of alcohol, central nervous system stimulants, opiates, barbiturates, and benzodiazepines. Additionally, religious observances, shift work, and trans meridian travel may also cause sleep disturbances, which may eventuate sleep deprivation. Physical activity, including leisure time activity, training, practice, and competition as well as meal timing and associated secretion of orexigenic hormones and culminating digestion and nutrient partitioning may also impact sleep patterns. Recently, light exposure has gained interest as research has identified it as a cause of sleep disruption. Exposure to compact fluorescent lights, light emitting diodes, and blue light emanating electronic devices including television and computer screens and smartphones have been shown to suppress pineal gland secretion of melatonin and interfere with the function of intrinsically photosensitive retinal ganglion cells (ipRGC). ipRGCs interact with the circadian rhythm and the brain’s suprachiasmatic nucleus (SCN) of the hypothalamus and thus altering signaling to the pineal gland (Bedrosian & Nelson, 2017). Prolonged exposure to bright light before bed was shown to increase depression risk, though depressive symptoms were not related to melatonin concentrations (Bedrosian & Nelson, 2017).
Recommendations to Prevent Sleep Deprivation
In consideration of the immense ergolytic and health effects, both short- and long-term, of sleep deprivation, organizations, including employers and sports teams, should aim to address sleep deprivation by employing or advocating a number of relatively simple measures. While authorities, including the American Academy of Sleep Medicine, have long advocated 7-9 hours of sleep for optimal health and performance among adults (Watson, 2017), they fail to address the role of sleep quality, which is a product of both sleep continuity and sleep efficiency. Good sleep quality is characterized by fewer disruptions and greater durations of deeper Rapid Eye Movement (REM) sleep that possesses bountiful restorative benefits, including memory consolidation, emotional processing, and brain development.
In order to achieve optimal sleep quality, a consistent bedtime and sleep duration should be implemented. For those desiring a new bedtime and trans meridian travelers, such as athletes and businesspersons, it is advised that the bedtime is adjusted in 15-to-30-minute increments. For those anticipating travel, schedules should be adjusted accordingly to accommodate the new time zone. For instance, if a game or performance is scheduled at 10p Pacific Time and the person is in the Eastern Time zone, they would practice at 1a locally leading up to the event. Additionally, exposure to bright lights, particularly fluorescent lights, light emitting diodes (LEDs), and blue light emanating electronic devices, should be avoided preceding bedtime. Also, the microenvironment of sleep should be considered, cooler ambient temperatures and lower humidity as well as comfortable clothing or bedding is recommended. Further, all electronics, except for an alarm clock and/or sound machine (which can promote relaxation), should be absent from the sleep microenvironment.
Individuals who are in sleep deprived states will have both neurocognitive and physical performance capabilities temporarily impeded. Acknowledging this, organizations, including coaches, fitness, and strength and conditioning professionals should adjust loading parameters of training and practice accordingly which warrant measurements. Hoffman (2014) proposed availing a visual analog scale or Likert scale to assess soreness, fatigue, energy, and focus. If resources are available, isometric grip strength assessments via hand dynamometer, postprandial blood draws, and heart rate variability monitoring may be conducted to ascertain training status and overtraining risk potentially magnified by sleep deprivation (Cronin, Lawton, Harris, Kilding, & McMaster, 2017; Hoffman, 2014; Lundstrom, Foreman, & Blitz, 2022).
To uphold health and performance of active individuals, including athletes, participating in events or related practices and training, it is imperative that fitness professionals are aware of the implications of sleep deprivation and adequately plan to prevent and account for it.
References
Bedrosian, T.A. & Nelson, R.J. (2017). Timing of light exposure affects mood and brain circuits. Translational Psychiatry. Advance online publication. https://doi.org/10.1038/tp.2016.262
Cheung, S.S. & Ainsle, P.N. (2022). Advanced environmental exercise physiology (2nd ed.). Champaign, IL: Human Kinetics.
Cho, J.W. & Duffy, J.F. (2019). Sleep, sleep disorders, and sexual dysfunction. The World Journal of Men’s Health, 37 (3): 261-275.
Cox, R.C. & Olatunji, B.O. (2020). Sleep in the anxiety-related disorders: a meta-analysis of subjective and objective research. Sleep Medicine Reviews. Advance online publication. https://doi.org/10.1016/j.smrv.2020.101282
Cronin, J., Lawton, T., Harris, N., Kilding, A., & McMaster, D.T. (2017). A brief review of handgrip strength and sport performance. Journal of Strength and Conditioning Research, 31 (11): 3187-3217.
Gabarino, S., Lanteri, P., Bragazzi, N.L., Magnavita, N., & Scoditti, E. (2021). Role of sleep deprivation in immune-related disease risk and outcomes. Communications Biology, 4 (1): 1304.
Hoffman, J. (2014). Physiological aspects of sport training and performance. (2nd ed.). Champaign, IL: Human Kinetics.
Kim, S.Y., Sim, S., Kim, S., & Choi, H.G. (2015). Sleep deprivation is associated with bicycle accidents and slip and fall injuries in Korean adolescents. PLoS One. Advance online publication. https://doi.org/10.1371/journal.pone.0135753
Lundstrom, C.J., Foreman, N.A., & Blitz, G. (2023). Practices and applications of heart rate variability monitoring in endurance athletes. International Journal of Sports Medicine, 44 (1): 9-19.
Mejri, M.A., Yousfi, N., Hammouda, O., Tayech, A., Ben Rayana, M.C., Driss, T., Chaouachi, A., & Souissi, N. (2016). One night of partial sleep deprivation increased biomarkers of muscle and cardiac injuries during acute intermittent exercise. The Journal of Sports Medicine and Physical Fitness, 57 (5): 643-651.
Milewski, M.D., Skaggs, D.L, Bishop, G.A., Pace, J.L., Ibrahim, D.A., Wren, T.A., & Barzdukas, A. (2014). Chronic lack of sleep is associated with increased sports injuries in adolescent athletes. Journal of Pediatric Orthopaedics, 34 (2): 129-133.
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Watson, A.M. (2017). Sleep and athletic performance. Current Sports Medicine Reviews, 16 (6): 413-418.
Yang, D., Shen, Y., Wu, C., Huang, Y., Lee, P., Er, N.X., Huang, W., & Tung, Y. (2019). Sleep deprivation reduces the recovery of muscle injury induced by high-intensity exercise in a mouse model. Life Sciences. Advance online publication. https://doi.org/10.1016/j.lfs.2019.116835