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In recent years, insufficient sleep has gained recognition as a global health concern, with researchers highlighting its pervasive impact. Prior studies indicate that approximately one-third of the world's population experiences symptoms of insomnia, and a staggering 70 million Americans grapple with various sleep disorders.

Individuals grappling with poor sleep often resort to coping mechanisms such as consuming caffeinated beverages during the day to combat fatigue. Paradoxically, some of these individuals also turn to alcohol at night, believing it aids in promoting better sleep. Shedding light on this intricate relationship, a groundbreaking study published in the journal PLOS ONE is the first to explore the combined effects of both substances – caffeine and alcohol – on overall sleep.

The Study

Researchers from the University of Washington School of Medicine conducted this study, revealing a paradoxical finding. Participants who engaged in the dual use of caffeine during the day and alcohol at night did not subjectively perceive a reduction in their sleep quality.

This contrasts with prior research that demonstrated the individual negative impacts of each substance on perceived sleep quality. The study suggests a potential false perception leading to a habitual self-medicating cycle, contributing to persistent poor sleep.

Frank Song, lead author and a fourth-year clinical psychology doctoral candidate, emphasised the novelty of their study. Despite prior knowledge of the adverse effects of caffeine and alcohol on sleep, no research had explored their combined impact on individuals' daily lives.

Regarding alcohol use, a study from October 2021 linked higher alcohol consumption to poorer sleep quality and shorter sleep duration. Another study from December 2019 reported that alcohol disrupts sleep by contributing to circadian rhythm abnormalities and increasing breathing-related sleep issues. Daytime caffeine use was also scrutinised, with a study from September 2023 revealing that caffeine can delay the onset of REM sleep. Past research indicates that while caffeine may help individuals stay awake during the day, its continued use can harm overall sleep quality.

To delve deeper into these interactions, Song and his team focused their investigation on 17 male, full-time financial traders over six weeks. The choice of financial traders, a population known for regular consumption of both caffeine and alcohol, aimed to mirror the lifestyles of many working adults.

Talking to Medical News Today, Mr Song explained “We chose to target financial traders because this is an adult population that consumes both caffeine and alcohol regularly, which we know both from research and my experience — I was an investment analyst on Wall Street so I worked alongside many traders,”

“Also, their profession requires high attention and cognitive speed, and so they value alertness and mental acuity during the day, which I think represents the lifestyles of many working adults,” he added.

Analysing the data, researchers found that individual consumption of caffeine reduced reported sleep quantity by an average of 10 minutes per cup consumed the previous day. Similarly, participants who consumed alcohol reported a 3% decrease in sleep quality per drink on average. Notably, the habitual use of alcohol to counteract the stimulant effects of caffeine and vice versa suggested a form of self-medication behaviour among participants.

In the realm of sleep quality perception, the study unveiled an intriguing interaction. The sedating effects of evening alcohol consumption seemed to offset some of the detrimental impacts of daytime caffeine consumption on sleep. However, this apparent improvement in perceived sleep quality may contribute to continued self-medication, masking the decline in actual sleep quality and leaving individuals unaware of their poor sleep.

Expert Insights

Dr. John Saito, a pulmonologist and member of the American Academy of Sleep Medicine Public Awareness Advisory Committee, expressed little surprise at these findings. He emphasised the neurotoxic and sedative nature of alcohol, which disrupts normal restorative sleep, contrasting with caffeine's stimulatory effects that reduce sleep duration.

“In the short term, taking chemicals for symptomatic relief is not new and thus, the observation that taking both caffeine and alcohol together altered perception of sleep quality was not surprising. Just like banging your head against the wall daily and taking cannabis and reporting that pain was not as severe as expected,” he said.

MNT also spoke with Dr. Monique May, a board-certified family physician and medical advisor for Aeroflow Sleep, about this study. She explained that “There is the potential for people to need more of either substance to balance themselves out, and that could become problematic given the addictive risk of alcohol,”

“People should be aware that alcohol tends to negatively affect the quality of sleep while caffeine negatively affects the quantity of sleep.”

“It is also important to point out that in the study there was also a small effect on sleep quality caused by caffeine, but to a lesser extent than that on sleep quantity. This ‘mismatch in perception between sleep quantity and sleep quality’ may explain why people still use caffeine despite its harmful effects on sleep,” Dr. May added.

Conclusion

In conclusion, this study adds a nuanced layer to our understanding of the complex interactions between caffeine, alcohol, and sleep, urging a more comprehensive approach to address the intricacies of sleep-related behaviours and habits.

This article was brought to you by HealthPlan, the expat health insurance specialist in Spain.

Source: Medical News Today