PMID 32595523

Research
All papers

Oral Contraceptive Use Influences On-Kinetic Adaptations to Sprint Interval Training in Recreationally-Active Women

Schaumberg MA, Stanley J, Jenkins DG, Hume EA, Janse de Jonge XAK, Emmerton LM, Skinner TL

Question

Does oral contraceptive use influence pulmonary, cardiovascular, and muscle oxygenation adaptations to sprint interval training in recreationally active women?

Summary

Recreationally active women completed 4 weeks of supervised cycle sprint interval training. Training improved time to fatigue in both oral-contraceptive users and naturally cycling women, but physiological adaptations differed by hormonal status: VO2 kinetics improved mainly in naturally cycling women, while muscle oxygenation kinetics improved mainly in oral-contraceptive users.

Methodology

  • 47 healthy recreationally active women grouped by oral contraceptive use.
  • 47 participants.
  • Wattbike cycling.
  • Work intervals: 1 min.
  • Recovery: 2 min passive recovery.
  • Intensity: 100-120% peak power output; maximal sustainable effort.
  • About 30 min interval block.
  • 3 sessions/week.
  • 4 weeks.
  • Non-randomized comparative intervention grouped by oral contraceptive status
  • Time to fatigue, VO2 kinetics, and Muscle oxygenation were tracked.

Outcomes

Time to fatigue

Both groups improved exercise tolerance.

Time to fatigue increased in both groups, p<0.001; no clear between-group difference.

Improved

VO2 kinetics

VO2 kinetics improved in naturally cycling women but not oral-contraceptive users.

MC improved at moderate p=0.021 and high p=0.015; group x time moderate p=0.020.

Mixed

TSI kinetics

Muscle tissue saturation kinetics improved in oral-contraceptive users but not naturally cycling women.

OC improved at moderate and high intensity, both p<0.001; group x time moderate p=0.001, high p<0.001.

Mixed

Insights

  • A 1:2 work-rest cycle SIT format improved performance in active women.
  • Adaptation mechanisms may vary by oral contraceptive status.
  • Mechanistic physiology findings should not be simplified into one-size-fits-all claims.

Limitations

  • Groups were not randomized by contraceptive status.
  • Short 4-week intervention.
  • Mechanistic outcomes may not map directly to user-facing benefits.
  • Safety and adherence reporting was limited.
  • Female hormonal subgroup findings limit generalizability.

Safety

  • Training was supervised and HR/RPE/power were recorded.
  • Adverse events and injuries were not clearly reported.