Effects of Hormonal Changes of the Menstrual Cycle on Cardiorespiratory Physiology and Exercise Performance during Incremental RAMP and Severe Intensity Exercise
Abstract
Fifteen females participated in an incremental ramp (RAMP) and severe intensity (SI) exercise protocol, both to volitional fatigue, during their follicular (FOL) and their luteal (LUT) phases of their menstrual cycle. Oxygen uptake (VO2), carbon dioxide production (VCO2), ventilation (VE), arterialized blood lactate [La-], and muscle deoxygenation (Δ[HHb]) were measured during testing. Throughout the duration of the RAMP (20-100%), VO2 was higher during the FOL phase (p=0.000850). However, VCO2, VE, La- and Δ[HHb] were unchanged between phases. For the SI (20-100%) protocol, there were no significant changes observed between phases for VO2, VCO2, VE, La-, or Δ[HHb]. Correlations between power output and VO2 during RAMP, in particular, were very high (0.90), suggesting, as others have suggested, that individual differences in menstrual phases symptoms may affect performance both positively and negatively in eumenorrheic females, despite no changes in the cardiorespiratory responses to maximal effort exercise bouts.