In a recent study published in the journal Dr BMJ Open, researchers evaluated the relationship between energy drink (ED) consumption and sleep characteristics among Norwegian students attending college and university. They also examined whether there were sex-based differences.
Energy drinks are non-alcoholic caffeinated beverages, often consumed for mental health and physical performance. Costs are common among students.
However, scientific data on energy drinks and sleep parameters in young adults are scarce and conflicting. Furthermore, most studies have used crude measures to assess sleep. More comprehensive sleep quality assessments, such as diagnostic guidelines for insomnia, could add to the body of literature.
The authors of the current study previously reported higher insomnia rates among young female students than their male counterparts; However, there was no significant sex-based difference in sleep duration.
About the study
In the current cross-sectional study, researchers assessed ED consumption frequency and related sleep characteristics among Norwegian students. Further, the study assessed whether these associations differ based on gender.
The Students’ Health and Well-Being SHOT2022 study, conducted by the Student Health and Well-Being Organization between February 8 and April 19, 2022, surveyed 53,266 individuals aged 18 to 35 years of higher education in Norway. Researchers collected data on participants’ gender, age, educational level, and relationship status from their national identity numbers.
The team assessed energy intake through food and drink questionnaires, focusing on ED consumption frequency. They reported participants’ bedtimes and waking times separately for weekends and weekdays.
Time in bed (TIB) was calculated based on the difference between bedtime and time in bed. They defined late bedtime as returning to bed after midnight. They assessed wakefulness after sleep onset (WASO) and sleep onset latency (SOL). Researchers calculated sleep duration by dividing sleep duration by the TIB value and multiplying by 100 and subtracting WASO and SOL from the TIB.
All participants reported experiencing periods of early morning awakening (EMA), difficulty initiating sleep (DIS), difficulty maintaining sleep (DMS), daytime fatigue and sleepiness, and sleep difficulty. The team operationalized insomnia using Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) guidelines: EMA, DMS, or DIS presence for three or more nights per week, daytime fatigue and sleeping three or more days per week, and three A period of difficulty sleeping for months or more.
Primary study outcomes were insomnia and sleep duration. The team performed general linear modeling (GLM) and used least significant difference (LSD) for post-hoc comparisons to assess associations between ED intake and continuous variables. They performed age-adjusted estimated marginal means (EMM) and log-linked binomial regressions to calculate effect sizes for age-adjusted dichotomous variables.
Of the 53,226 participants, the average age was 24, and 66% were female. ED expenditure frequency was inversely associated with sleep duration and efficiency. Frequency of ED intake was directly related to sleep patterns such as SOL and WASO across gender.
High ED consumption was associated with an increased risk of sleep problems across all sleep parameters, with the strongest association observed between daily ED consumption and short sleep duration, with risk ratios (RR) of 2.1 and 1.9 in men and women, respectively.
There were significant gender-based differences in ED use, with 50% of women and 40% of men reporting infrequent use. Women take less ED than men.
Women and men who drank energy drinks daily slept 30 minutes less than those who rarely or never consumed ED. The team found a similar relationship between SOL and WASO; Increased frequency of ED consumption was associated with increased nocturnal waking time and time falling asleep.
Insomnia was prevalent among 51% of female daily ED consumers, 33% among women who never or rarely drank energy drinks, with a similarly graded pattern among men (37% vs. 22%, respectively).
Men showed stronger correlations with ED intake for sleep parameters. Compared with infrequent or never ED consumers, regular male consumers had a 2.0-fold greater risk of sleeping less than six hours (hazard ratio, 2.1), a similar pattern for women (hazard ratio, 1.9).
Infrequent ED use (one to three times a month) was significantly associated with higher odds of poor sleep quality for most sleep characteristics, except for late bedtimes and shorter sleep duration for men and women.
Research findings have shown that excessive ED consumption significantly affects sleep outcomes, even in small amounts associated with poorer sleep. The study highlights the need for more attention to the outcomes of ED uptake among students.
ED consumption frequency had a dose-response relationship with sleep difficulty, sleep duration, and insomnia. Regular ED intake increases the likelihood of sleep difficulties for both men and women.