Consuming caffeinated drinks like coffee, tea, or soda four hours before bedtime may not disrupt sleep quality.
The finding comes after researchers examined the link between caffeine, nicotine, and alcohol consumed within four hours of bedtime on sleep duration, sleep efficiency, and wake after sleep onset among 785 participants from the Jackson Heart Sleep Study (an African-American cohort).
Study participants wore a wrist-watch-like sensor and recorded in a daily sleep diary how much of each substance they consumed within four hours of bedtime, totaling 5,164 days and night’s worth of data.
While alcohol and nicotine interfered with a full night’s rest, researchers found no link between caffeine consumption with any of the sleep parameters. However, the researchers added that caffeine dosing and variations in caffeine sensitivity and tolerance vary from person to person, and was not captured during this study. These measurements could play an important role in the association between caffeine use and sleep.
Researchers also found that nicotine interfered with sleep duration, especially among participants with insomnia resulting on average of 43 minutes less in sleep duration. The study, published in the journal Sleep, was funded by NHLBI.