PURPOSE: This study aimed to examine the acute effect of caffeine on exercise capacity, exercise-related fatigue, and functional performance in prostate cancer survivors.
METHODS: In this randomized, placebo-controlled, double-blind crossover study, 30 prostate cancer survivors (age, 70.3 ± 7.7 yr; body mass, 80.5 ± 13.0 kg; mean ± SD) consumed 6.04 ± 0.16 mg·kg(-1) of anhydrous caffeine or a placebo 1 h before completing a battery of exercise capacity and functional performance tests. Testing sessions were separated by 3-4 wk. Immediate fatigue and perceived exertion were measured directly pre- and postexercise at both testing sessions.
RESULTS: Caffeine increased exercise capacity by 7.93 s (+3.0%; P = 0.010); however, postexercise fatigue and perception of exertion were comparable with the placebo session (P = 0.632 and P = 0.902, respectively). Increases in isometric grip strength trended toward significance in both dominant (+2.9%; P = 0.053) and nondominant (+2.1%; P = 0.061) hands in the caffeine trial compared with placebo. Caffeine ingestion did not result in improvements in performance for any of the remaining functional measures, including the timed up-and-go test, repeated chair stands, 6-m fast walk, and 6-m backward tandem walk. Systolic blood pressure and HR were significantly increased (P = 0.006 and P = 0.040, respectively) upon completion of the testing battery when compared with placebo.
CONCLUSIONS: Consumption of caffeine 1 h before exercise induced improvements in exercise capacity and muscular strength in prostate cancer survivors. However, there was no change in exercise-related fatigue when compared with placebo despite reduction in timed performance of the 400-m walk. Caffeine seems to enhance exercise tolerance through improved performance with no subsequent increase in fatigue or perception of exertion and may be an appropriate strategy to promote exercise participation in prostate cancer survivors.
2015. Vol. 47, no 3, 468-75 p.