1. [4] RESULTS
The decreases in blood pressures that follow a single bout of exercise (post exercise
hypotension: PEH) are well documented in both hypertensive and normotensive
individuals (Coats et al., 1989; Reuckert et al., 1996), and indeed resting blood
pressure is often normalized following acute exercise in hypertensives (Arakawa,
1993). Although the magnitude of PEH seems to be unaffected by gender, the impact
of menstrual cycle phase upon gender comparisons has been ignored.
We studied 8 females (age: 20±0.3 yr) during the early follicular (EF), late follicular
(LF) and mid-luteal (ML) phases of the menstrual cycle, and 8 males (age: 21±0.7 yr)
on 2 separate occasions (M1 and M2). Cycle phase was determined via urinary
assessment of LH. Central and peripheral haemodynamics were recorded via
echocardiography and venous occlusion plethysmography (Fig. 1), at rest and for 45
min following 30 min of cycle ergometry at 80% of the lactate threshold.
This is the first study to examine the influence of menstrual cycle phase upon gender
differences in PEH. We demonstrated that gender affects the magnitude and
haemodynamic mechanisms regulating PEH. Immediately post-exercise, females
demonstrated a greater reliance in stroke volume, whilst males relied on a greater left
ventricular end systolic volume and HR in order to maintain post-exercise CO in the
presence of peripheral vasodilation. Systemic vascular resistance was non-
significantly lower in males than females probably as a result of a greater body size.
Furthermore, menstrual cycle phase appears to influence the pattern of PEH such
that pressures are lower in those phases concurrent with low reproductive hormone
concentrations. Enhanced buffering of peripheral vasodilation in the LF and ML
phases meant that gender differences in MAP and DBP were evident in the EF phase
of the cycle.
This study was supported by the School of Sport and Exercise Sciences of the
University of Leeds.
The aim of the present study was to examine central and peripheral haemodynamics
regulating PEH following moderate-intensity exercise in moderately active males and
females. The impact of menstrual cycle phase upon potential gender differences was
examined by investigating females in three phases of their cycle.
[1] INTRODUCTION
INFLUENCE OF MENSTRUAL CYCLE PHASE UPON GENDER DIFFERENCES IN POST EXERCISE HYPOTENSION
Joseph I. Esformes, Katherine Bird, Jennifer Cornes, Frances Norman, Andrew Roberts, Joanna Sigley, Karen M. Birch.
School of Sport & Exercise Sciences, University of Leeds, Leeds, United Kingdom.
[2] AIMS
[3] METHODS
[7] REFERENCES
[5] SUMMARY
[6] CONCLUSION
Both males and females in this study demonstrated a classic pattern of post-exercise
recovery in all blood pressure variables. However, cardiovascular recovery from
exercise appears to differ between males and females and this difference is further
influenced by menstrual cycle phase.
Haemodynamics at rest did not differ between males and females or between the
testing phases (P > 0.05; Table 1). Significant PEH was observed in all subjects (P <
0.05) with the magnitude of the nadir in all blood pressure variables being
significantly greater (P < 0.05) in females compared to males; 10±1 vs 4±1, 9±1 vs
5±1, 8±1 vs 4±1 for systolic blood pressure (SBP), diastolic blood pressure (DBP) and
mean arterial pressure (MAP), respectively. Blood pressure responses did not differ
between tests in males, whilst females demonstrated a lower DBP and MAP (Fig. 2)
throughout recovery in the EF phase compared to the LF and ML phases (P <0.05).
This variation resulted in a phase-by-gender interaction with DBP and MAP
demonstrating a different pattern of recovery in females compared to males in the EF
phase only (P < 0.05).
SBP displayed a gender-by-time interaction, indicating a different temporal pattern of
recovery in each gender (Table 1; P< 0.05). Mean values for central and peripheral
haemodynamics reported for both males and females are displayed over time in Table
1. Cardiac output (CO; Fig. 3) and heart rate (HR) displayed gender-by-time
interactions (P < 0.05). Both values were significantly greater than rest at 5 min
recovery, but this increase was larger in males than in females (P < 0.05: CO,
31±0.7% vs 15±6.8 %; HR, 26±0.3 % vs 3±3.2 %).
Fig. 1 Venous occlusion plethysmography in the lower limb and echocardiographic
measurements obtained from the left parasternal long axis view of the heart.
Central haemodynamic indices were unaffected by menstrual cycle phase, whilst calf
blood flow and systemic vascular resistance were unaffected by either menstrual
phase or gender (P > 0.05).
Fig. 2 Mean arterial pressure
(MAP) recorded at baseline
(0 on the time axis) and
throughout the recovery
period. * P < 0.05 versus 0.
Table 1. Post-exercise cardiovascular data
Fig. 3 Cardiac output (CO)
recorded at baseline (0 on
the time axis) and throughout
the recovery period. * P <
0.05 versus 0; ** P < 0.05
versus 5 min.
AMERICAN COLLEGE OF SPORTS MEDICINE ∙ 52ND ANNUAL MEETING ∙NASHVILLE ∙TENNESSEE ∙ JUNE 1 – 4, 2005
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