Most Major Side Effects of Caffeine Experienced by Young Adults Are Acute Effects and Are Related to Their Weekly Dosage Ingested

T J Babwah et al, 2018.
Journal of Caffeine and Adenosine Research, Volume 8 (1).
March 22, 2018



To determine the use of products containing caffeine, the side effects associated with this use, the timing of the side effects after consumption, and whether there is a relationship between the development of side effects and the dose of caffeine consumed among young adults. A threshold level of weekly caffeine consumption is being sought in this population, above which there are increased side effects.


A cross-sectional study using convenience sampling strategy was adopted by using a self-administered newly designed questionnaire.


Secondary schools, one postsecondary institute, and the University of the West Indies were used. Subjects:




The response rate was 391/412 (94.9%). Significant dose-dependent relationships between the dose of weekly caffeine consumed and: (i) the frequency of occurrence of palpitations ( p = 0.001) and (ii) the frequency of sleep disturbances ( p = 0.001) were observed. Doses of weekly caffeine consumption of >428.5 mg were significant predictors for headaches, restlessness, and state anxiety in this population. All symptoms, except a depressed feeling, occurred most commonly within 4 hours of consumption of caffeinated products and were mainly attributed to colas, coffee, and teas by participants. A depressed feeling was more attributed to energy drinks.


Most side effects were related to the acute effects of caffeine, but depressed feeling was more commonly reported as a withdrawal effect of caffeine. Caffeine intake in this young adult population should be recommended to be less than 428.5 mg/week in an attempt to reduce the occurrence of these side effects.


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