RESUMO
AIM: The aim of the present study is to review the effects of caffeine abstinence on the quality of sleep. BACKGROUND: Insomnia is a common problem and abstinence from caffeine is the most popular component in sleep hygiene advice. However, there have been inconsistent results relating to the effectiveness of caffeine abstinence in improving sleep. DESIGN: Systematic review. METHODS: We browsed several electronic databases and reference lists of articles about the correlation of caffeine consumption and sleep deprivation. We selected the articles according to predefined inclusion and exclusion criteria. Two reviewers assessed the quality of trials, which were selected according to the Jadad quality assessment scale. We included the trials scoring three or above in the systematic review and extracted their data. We assessed the heterogeneity of the studies before we considered whether or not to combine the studies' results. RESULTS: Three randomised control trials fulfilled the selection criteria among which two trials scored > or =3 on the Jadad scale. We included these two trials in our systematic review. The designs and outcome measurements of these two trials were not homogeneous, therefore, we did not combine their results. Instead, we conducted a critical appraisal. In one trial, caffeine abstinence was associated with significant lengthening of sleep duration (p < 0.01) and better sleep quality (p < 0.05). In another trial, subjects had less difficulty falling asleep on days when they drank decaffeinated coffee (p < 0.05). CONCLUSIONS: The results showed that caffeine abstinence for a whole day could improve sleep quality. Thus, health practitioners were recommended to include caffeine abstinence in the instructions for sleep hygiene. RELEVANCE TO CLINICAL PRACTICE: This study demonstrates the effectiveness of caffeine abstinence in improving sleep quality. It provides evidence for the practice of including caffeine abstinence in sleep hygiene advice.
