A new study has found that young Canadians who use pre-workout supplements are more than twice as likely to report sleeping five hours or less per night, compared to those who do not use these products. The research, published in Sleep Epidemiology, raises concerns about the potential effects of workout stimulants on sleep quality, recovery, and next-day performance among adolescents and young adults.
The study analyzed data from Wave 2 of the Canadian Study of Adolescent Health Behaviors. Researchers surveyed individuals aged 16 to 30 across Canada using an online platform that included measures to prevent fraudulent responses. Ethics approval was obtained from the University of Toronto Health Sciences Research Ethics Board.
Participants reported their use of pre-workout supplements in the previous year and provided information about their average nightly sleep over the past two weeks. Supplement use was categorized as any use versus none, while sleep duration was grouped into five categories: five hours or less, six hours, seven hours, eight hours (used as a reference), or nine or more hours.
About 22% of respondents had used pre-workout supplements within the past year. The most common reported sleep duration was seven hours per night (34.9%), with only about one-fifth meeting the recommended eight-hour guideline for this age group.
Researchers used multinomial logistic regression to analyze associations between supplement use and sleep patterns while adjusting for factors such as age, gender identity, race/ethnicity, sexual orientation, education level, symptoms of depression and anxiety (measured by PHQ-9 and GAD-7), and recent weight training activity.
The results showed that those who used pre-workout supplements were more than twice as likely to get five hours or less of sleep per night compared with peers who typically slept eight hours. No significant association was found between supplement use and getting six, seven, or nine-plus hours of sleep.
The findings align with existing knowledge regarding caffeine—a common ingredient in many pre-workout products—which is known to disrupt normal sleep–wake cycles if consumed close to bedtime. Adolescents and young adults often train after school or work when supplement intake may occur near bedtime.
While researchers controlled for mood symptoms and exercise habits in their analysis, they noted that because this is a cross-sectional study it cannot determine causality—whether taking supplements causes shorter sleep or whether people with short sleep turn to these products for energy.
Still, researchers highlight that even occasional use could increase risk for very short sleep durations well below recommended guidelines. Fewer than one-third of participants achieved at least eight hours’ rest each night—pointing toward a broader issue with insufficient sleep among youth.
“Given how often workouts occur late in the day, timing appears central: stimulant intake close to bedtime can undermine recovery, learning, mental health, and athletic goals. Practical guidance should emphasize avoiding pre-workouts well before bedtime, reading labels for caffeine content, and prioritizing sleep hygiene at home,” stated the authors.
They recommend future research examine dose amounts and timing relative to bedtimes in order to inform educational campaigns and clinical practice aimed at supporting healthy behaviors among young people.
