The physiological effect of early pregnancy on a woman’s response to a submaximal cardiopulmonary exercise test

Abstract

Given all its systemic adaptive requirements, pregnancy shares several features with physical exercise. In this pilot study, we aimed to assess the physiological response to submaximal cardiopulmonary exercise testing (CPET) in early pregnancy. In 20 healthy, pregnant women (<13 weeks gestation) and 20 healthy, non‐pregnant women, we performed a CPET with stationary cycling during a RAMP protocol until 70% of the estimated maximum heart rate (HR) of each participant. Hemodynamic and respiratory parameters were non‐invasively monitored by impedance cardiography (PhysioFlow®) and a breath‐by‐breath analyzer (OxyconTM). To compare both groups, we used linear regression analysis, adjusted for age. We observed a similar response of stroke volume, cardiac output (CO) and HR to stationary cycling in pregnant and non‐pregnant women, but a slightly lower 1‐min recovery rate of CO (−3.9 [−5.5;‐2.3] vs. −6.6 [−8.2;‐5.1] L min−1 min−1; p = .058) and HR (−38 [−47; −28] vs. −53 [−62; −44] bpm/min; p = .065) in pregnant women. We also observed a larger increase in ventilation before the ventilatory threshold (+6.2 [5.4; 7.0] vs. +3.2 [2.4; 3.9] L min−1 min−1; p < .001), lower PETCO2 values at the ventilatory threshold (33 [31; 34] vs. 36 [34; 38] mmHg; p = .042) and a larger increase of breathing frequency after the ventilatory threshold (+4.6 [2.8; 6.4] vs. +0.6 [−1.1; 2.3] breaths min−1 min−1; p = .015) in pregnant women. In conclusion, we observed a slower hemodynamic recovery and an increased ventilatory response to exercise in early pregnancy.

Assessment of physical fitness during pregnancy: validity and reliability of fitness tests, and relationship with maternal and neonatal health – a systematic review

“…Regarding aim 1, 99 tests (including 75 different protocols) were used to assess CRF,8 12 13 18 27–108 28 (including 16 different protocols) to assess muscular fitness,8 12 13 61 86 109–122 14 (including 13 different protocols) to assess flexibility,12 13 110 114 123–127 45 tests (including 40 different protocols) to assess balance,110 116 128–167 2 tests using the same protocol to assess speed168 169 and 3 tests using the same protocol were multidimensional 168–170. No results were found for other PF components such as agility or coordination.…”

Assessing physical fitness during pregnancy: validity and reliability of fitness tests, and relationship with maternal and neonatal health-related outcomes. A systematic review

“…physiological variables such as %HR max or %VO 2max, and other used absolute intensity, such as specific HR (beats per minute). Among the studies that used %HR max as a test termination criterion, there was a variety of percentages such as 70%[48,58,65,96], 75%[46,61,91,107] or 85%[13,40,81]. Among the studies that used %VO 2max , there were different percentages such as 40%[54], 50% [53,59], 60%[52,54], or 70%[178].…”

“…There have been more incremental tests used for CRF tests during pregnancy compared to steady-state tests and more submaximal compared to maximal tests.There is no consensus regarding test termination criteria for submaximal tests, which undoubtedly needs further research. Some articles used relative intensity using Some articles used the traditional 220-age formula[61,65,81,91,107] while others used the Karvonen[40] or Tanaka[96] formulas. Some articles did not specify how HR max was estimated[46,48,58].…”

“…This heterogeneity could be due to the physiological complexity of the pregnant woman, in terms of cardiac changes and response to exercise and the lack of scientific information in this regard. Moreover, the gestational week could be a determinant for physiological response since Bijl et al[96] observed a slower hemodynamic recovery and an increased ventilatory response to exercise in early pregnancy compared to non-pregnant women. With regards to the maximal tests, different terms have been used like maximal criteria such as volitional fatigue[64,69,70,72,73,93,94,109,178], exhaustion[63], anaerobic threshold…”

“…Some articles used the traditional 220-age formula[61,65,81,91,107] while others used the Karvonen[40] or Tanaka[96] formulas. Some articles did not specify how HR max was estimated[46,48,58].…”