THE EFFECTS OF ACUTE YOHIMBINE HYDROCHLORIDE INGESTION ON DIURNAL CHANGES IN EXERCISE PERFORMANCE
Megan Barnes, Camryn Cowan, Rebecca Rogers, Christopher Ballmann, FACSM. Samford University, Birmingham, AL.
Diurnal fluctuations in exercise ability may confound training and competition performance during morning hours. Yohimbine hydrochloride (YHM) is an alpha-2-adrenergic receptor antagonist which induces sympathetic stimulation via catecholamine release. While YHM ingestion has been shown to acutely improve exercise performance when time of day is standardized, it is unknown if YHM counteracts performance decrements associated with early morning times. Thus, the purpose of this study was to investigate if acute YHM ingestion influences rowing performance at varying times of day. Physically active females participated in three counterbalanced rowing time trials: 1) Morning-Placebo (AM-PL), 2) Morning-Yohimbine (AM-YHM), and 3) Afternoon-Control (PM). For each AM trial, participants consumed their respective treatment 20 minutes before exercise while no treatment was given for PM. Participants then completed a 2000m rowing time trial while power output, time to completion (TTC), and HR were recorded each minute. Blood [La-] was measured pre- and post-exercise. Findings showed that YHM ingestion resulted in greater power output (p= 0.045) and faster TTC (p=0.044) compared to PL during AM trials. HR was not significantly different between any trials (p< 0.05). Blood [La-] was significantly lower post-exercise with YHM ingestion versus PL (p=0.012) during AM trials. No other differences for HR, power output, TTC, or [La-] existed between trials (p> 0.05). These findings suggest that acute YHM ingestion may counteract performance decrements during AM times which could possibly improve training or competition outcomes during early times of day.
Barnes, M; Cowan, C; Rogers, R; and Ballmann, FACSM, C
"THE EFFECTS OF ACUTE YOHIMBINE HYDROCHLORIDE INGESTION ON DIURNAL CHANGES IN EXERCISE PERFORMANCE,"
International Journal of Exercise Science: Conference Proceedings: Vol. 16:
2, Article 331.
Available at: https://digitalcommons.wku.edu/ijesab/vol16/iss2/331