The Effects of Energy Drinks on Sleep and Daily Functioning

Caffeinated energy drinks are popular among young people (Reissing et al., 2009). The relatively high doses of caffeine in energy drinks and lack of regulations are concerning as caffeine can cause adverse physical and psychological effects, especially at high doses and among non-tolerant individuals. Energy-drink related ER visits doubled from 2007 to 2011, with most cases involving individuals 18 to 25 years old (SAMHSA, 2014). In addition to these serious acute effects, it is possible that energy drinks could be adversely affecting the sleep and daily functioning of users even when consumed at moderate doses that are not likely to cause acute caffeine intoxication. However, there is very little controlled research in this area. The goal of this study was to examine the effects of energy drink consumption on sleep and mood in a sample of young adults. Participants (n=24) consumed one energy drink each day for 28 days. Energy drinks contained no caffeine during weeks 1 and 4 and 200 mg caffeine during weeks 2 and 3. Participants were assessed once daily on sleep and liking of the drink and twice daily on mood and other caffeine-related symptoms. Participants reported significantly greater sleep disturbance during weeks they consumed caffeinated energy drinks compared to placebo energy drinks. Furthermore, participants reported greater jitteriness, lower fatigue and fewer headaches during caffeine weeks compared to placebo weeks. These findings are among the first to show a direct causal link between energy drink consumption and greater sleep disturbance and other effects among young adults. These findings warrant further investigation of the possible adverse effects of energy drinks and have implications for the regulation of caffeine content in energy drinks.