Abstract
Purpose: To examine the impact of oral contraceptive (OC) phases on performance, physiological, and subjective responses to prolonged, intensive exercise when carbohydrate (CHO) stores are reduced.
Methods: Ten well-trained female cyclists using monophasic OC completed 4 identical trials (>150 min) under conditions of in-trial 60-g·h −1 CHO supplementation (CHO+) or placebo (CHO−) during the sugar- (SUG) and active-pill (ACT) phases of their OC cycle. Each trial comprised two 400-kcal time trials (TT) separated by 1 hour of submaximal cycling at first ventilatory threshold.
Results: Change in completion time from TT 1 to TT 2 was minimized in CHO+ compared with CHO− (4.06 [2.55] vs 6.08 [5.33] min; P = .019, effect size = −0.36). An interaction effect of OC and CHO was observed for time to complete TT ( P = .006), mean TT power ( P = .002), mean TT heart rate ( P = .002), and posttrial emotional balance ( P = .020) and negative emotional state ( P = .033). In ACT, mean TT power and heart rate were higher in CHO+ when compared with CHO−, resulting in faster TTs in CHO+ and improved post-trial emotional well-being. When CHO was not supplemented, TT power and heart rate were higher in SUG when compared with ACT, resulting in faster TTs in SUG and improved post-trial emotional balance.
Conclusion: CHO depletion during ACT negatively influenced TT performance and emotional well-being when compared with SUG. Irrespective of OC pill phase, CHO supplementation should be prioritized to sustain performance and improve post-exercise recovery–stress balance.