Oral contraceptive cycle phase does not affect 200-m swim time trial performance

Area of Science:

• Sports Science
• Endocrinology
• Physiology

Background:

• Hormonal fluctuations during the menstrual cycle can influence athletic performance.
• The impact of monophasic oral contraceptives (OCs) on female athlete performance requires further investigation.

Purpose of the Study:

• To investigate the effect of acute hormonal changes within a monophasic OC cycle on 200-m swimming performance.
• To analyze physiological markers and performance metrics across different phases of an OC cycle.

Main Methods:

• Six competitive swimmers/water polo players completed a 200-m time trial during three OC cycle phases: consumption (CONS), early withdrawal (WITH1), and late withdrawal (WITH2).
• Performance data (split times, stroke rate) and physiological markers (heart rate, blood lactate, glucose, pH) were recorded.
• Resting serum estradiol and progesterone were measured.

Main Results:

• No significant differences were found in body composition, 200-m swim time, stroke rate, peak heart rate, or blood glucose between OC phases.
• Peak blood lactate was significantly lower and blood pH higher during the late withdrawal phase (WITH2) compared to the consumption phase (CONS).
• Estradiol levels were significantly higher during WITH2 compared to WITH1 and CONS.

Conclusions:

• Monophasic OC use does not negatively impact 200-m swimming performance based on cycle phase.
• Reduced blood lactate and increased pH during withdrawal may be linked to fluid retention and cellular alkalosis.
• Female swimmers using monophasic OCs can compete without concern for cycle phase, but coaches should consider OC use when interpreting lactate data.