Caffeine Better in the Morning or Afternoon?
To determine whether the ergogenic effects of caffeine ingestion on neuromuscular performance are similar when ingestion takes place in the morning and in the afternoon. Thirteen resistance-trained males carried out bench press and full squat exercises against four incremental loads (25%, 50%, 75% and 90% 1RM), at maximal velocity. Trials took place 60 min after ingesting either 6 mg kg−1 of caffeine or placebo. Two trials took place in the morning and two in the afternoon, all separated by 36–48 h. At the end of the study, plasma caffeine increased similarly during AM and PM workouts. Despite similar blood caffeine levels during both trials only the morning sessions produced an increase in muscle power output in the squat. Additionally, The negative side effects of caffeine were more prevalent in the afternoon trials (13 vs. 26%). The ingestion of a moderate dose of caffeine counteracts the muscle contraction velocity declines observed in the morning against a wide range of loads. Caffeine effects are more evident in the lower body musculature. Evening caffeine ingestion not only has little effect on neuromuscular performance, but increases the rate of negative side-effects reported.To sum up the study, caffeine resulted in greater muscle performance in the squat taken in the morning and also resulted in less side effects than taken in the afternoon.
Mora Rodriguez, R, Pallarés, JG, López Samanes, Á, Fernández, Elias, VE, Ortega, JF. Improvements on neuromuscular performance with caffeine ingestion depend on the time of day. Journal of Science and Medicine in Sport. Volume 18, Issue 3, May 2015, Pages 338–342
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