AUTHOR=Taipale-Mikkonen Ritva S. , Raitanen Anna , Hackney Anthony C. , Solli Guro Strøm , Valtonen Maarit , Peltonen Heikki , McGawley Kerry , Kyröläinen Heikki , Ihalainen Johanna K. 

TITLE=Influence of Menstrual Cycle or Hormonal Contraceptive Phase on Physiological Variables Monitored During Treadmill Testing

JOURNAL=Frontiers in Physiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2021.761760

DOI=10.3389/fphys.2021.761760

ISSN=1664-042X

ABSTRACT=<p><bold>Purpose:</bold> To examine the influence of menstrual cycle (MC) and hormonal contraceptive (HC) cycle phases on physiological variables monitored during incremental treadmill testing in physically active women (eumenorrheic, EUM = 16 and monophasic HC-users, CHC = 12).</p><p><bold>Methods:</bold> Four running tests to exhaustion were performed at bleeding, mid follicular (mid FOL)/active 1, ovulation/active 2, and mid luteal (mid LUT)/inactive. HC and MC phases were confirmed from serum hormones. Heart rate (HR), blood lactate (Bla), and <inline-formula><mml:math id="ieq1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2</sub> were monitored, while aerobic (AerT) and anaerobic (AnaT) thresholds were determined. <inline-formula><mml:math id="ieq2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2peak</sub>, maximal running speed (RUN<sub>peak</sub>), and total running time (RUN<sub>total</sub>) were recorded.</p><p><bold>Results:</bold> No significant changes were observed in <inline-formula><mml:math id="ieq3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2</sub> or Bla at AerT or AnaT across phases in either group. At maximal effort, absolute and relative <inline-formula><mml:math id="ieq4" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mtext>V</mml:mtext><mml:mo>˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2peak</sub>, RUN<sub>peak</sub>, and RUN<sub>total</sub> remained stable across phases in both groups. No significant fluctuations in HR<sub>max</sub> were observed across phases, but HR at both AerT and AnaT tended to be lower in EUM than in CHC across phases.</p><p><bold>Conclusion:</bold> Hormonal fluctuations over the MC and HC do not systematically influence physiological variables monitored during incremental treadmill testing. Between group differences in HR at AerT and AnaT underline why HR-based training should be prescribed individually, while recording of MC or HC use when testing should be encouraged as phase may explain minor, but possibly meaningful, changes in, e.g., Bla concentrations or differences in HR response.</p>