The Impact Of Alcohol On Sleep

Alcohol consumption can have a significant impact on the neurophysiology of sleep, affecting both the structure and quality of sleep. Here are five ways that alcohol can affect our sleep.

Suppression of REM sleep

Alcohol consumption has been found to suppress Rapid Eye Movement (REM) sleep, which is the stage of sleep associated with dreaming and memory consolidation. This can result in a decrease in overall sleep quality, as well as potentially increasing the likelihood of experiencing nightmares. Neurophysiologically, alcohol reduces the activity of the brain's prefrontal cortex, which is responsible for regulating REM sleep. (Ebrahim et al., 2013; Colrain & Baker, 2011)

Increased delta activity
While alcohol consumption may initially help individuals fall asleep faster, it can also lead to an increase in slow-wave activity, or delta activity, during the first half of the night. This is because alcohol can disrupt the body's natural sleep cycle and interfere with the natural progression from wakefulness to sleep. Delta activity is typically associated with deep, restorative sleep, but excessive delta activity can lead to fragmented sleep and daytime sleepiness. (Ebrahim et al., 2013; Colrain & Baker, 2011)

Disruption of sleep architecture
Alcohol consumption can also disrupt the normal sleep architecture, leading to fragmented sleep and decreased sleep efficiency. This can result in a decrease in overall sleep quality and can lead to feelings of fatigue and grogginess the next day. Neurophysiologically, alcohol disrupts the balance between the brain's inhibitory and excitatory neurotransmitters, leading to a less stable sleep architecture. (Ebrahim et al., 2013; Colrain & Baker, 2011)

Suppression of respiratory drive
Alcohol consumption can lead to a suppression of respiratory drive during sleep, which can worsen the symptoms of sleep apnea or increase the likelihood of developing sleep apnea in individuals who are already at risk. This is because alcohol can reduce the activity of the brainstem neurons that control breathing. (Redline et al., 2000; Smith & Sullivan, 2006)

Increased arousal threshold
Alcohol consumption can increase the arousal threshold during sleep, meaning that it takes a stronger stimulus to wake an individual up from sleep. While this may seem like a positive effect of alcohol on sleep, it can actually lead to more fragmented sleep and decreased sleep quality overall. Neurophysiologically, alcohol reduces the activity of the brain's arousal systems, making it more difficult to wake up when necessary. (Ebrahim et al., 2013; Colrain & Baker, 2011)

Overall, alcohol consumption can have a significant impact on the neurophysiology of sleep, affecting both the structure and quality of sleep. Individuals who are looking to improve their sleep should aim to avoid consuming alcohol close to bedtime.

References
Colrain, I. M., & Baker, F. C. (2011). Alcohol and the sleeping brain. Handbook of Clinical Neurology, 98, 597-618.
Ebrahim, I. O., Shapiro, C. M., Williams, A. J., & Fenwick, P. B. (2013). Alcohol and sleep I: effects on normal sleep. Alcoholism: Clinical and Experimental Research, 37(4), 539-549.
Redline, S., Tishler, P. V., Hans, M. G., Tosteson, T. D., Strohl, K. P., Spry, K., & Gottlieb, D. J. (2000). Racial differences in sleep-disordered breathing in African-Americans and Caucasians. American Journal of Respiratory and Critical Care Medicine.