concept

normoxia

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Sex differences in cardiorespiratory control under hypoxia - Frontiers frontiersin.org Frontiers Jan 30, 2025 22 facts

measurementUnder normoxia, males have a cardiac output (CO) of 6.43 ± 0.76 L.min−1 and females have 6.99 ± 0.96 L.min−1; under iso-saturation hypoxia, males have 6.85 ± 0.91 L.min−1 and females have 7.46 ± 1.16 L.min−1.

measurementUnder normoxia, males have a cardiac index (CI) of 3.45 ± 0.33 L.min−1.m2 and females have 4.26 ± 0.42 L.min−1.m2; under iso-saturation hypoxia, males have 3.64 ± 0.34 L.min−1.m2 and females have 4.54 ± 0.55 L.min−1.m2.

measurementIn a study of cardiorespiratory responses, males under normoxia had a heart rate of 74 ± 10 bpm, while females under normoxia had a heart rate of 83 ± 6 bpm.

claimAdult females may present with higher oxygen saturation than males in normoxia, though this difference is not evident in newborns or prepubertal children.

measurementThe cardiac index (CI) for males was 3.45 ± 0.33 L.min−1.m2 under normoxia and 3.64 ± 0.34 L.min−1.m2 under iso-saturation hypoxia.

measurementFemales had a tidal volume (Vt) of 747 ± 125 ml under normoxia and 753 ± 116 ml under iso-saturation hypoxia.

measurementUnder normoxia, males have a heart rate (HR) of 74 ± 10 bpm and females have 83 ± 6 bpm; under iso-saturation hypoxia, males have 77 ± 8 bpm and females have 90 ± 7 bpm.

measurementIn a study of 22 healthy individuals (12 females), participants were exposed to 10 minutes of normoxia (FiO2 = 0.21) followed by 10 minutes of hypoxia (FiO2 = 0.115).

procedureThe study on sex differences in cardiorespiratory control under hypoxia used an oxygen dilution system (Everest Summit II—Hypoxico®, NY, USA) coupled with two 200-L non-diffusing gas reservoirs to control the fraction of inspired oxygen (FiO2) for normoxic and hypoxic conditions.

measurementThe alpha index of low-frequency components (α–LF) for males was 10.1 ± 5.6 ms.mmHg−1 under normoxia and 9.0 ± 5.3 ms.mmHg−1 under iso-saturation hypoxia.

procedureThe researchers calculated physiological changes induced by hypoxia using the delta formula (Δ = hypoxia—normoxia) for both male and female groups.

measurementUnder normoxia, males have a pulse oxygen saturation (SpO2) of 98 ± 1% and females have 98 ± 1%; under iso-saturation hypoxia, males have 91 ± 3% and females have 92 ± 2%.

measurementIn normoxia, females had lower sympathetic vascular modulation (estimated by the LF spectral component of systolic blood pressure) but similar spontaneous cardiac baroreflex sensitivity compared to males.

procedureHeart rate variability (HRV) analysis involves analyzing beat-to-beat time series of R-R intervals using a 300-beat time window, focusing on the last 5 minutes for normoxia and iso-time hypoxia conditions.

measurementFemales had a minute ventilation (VE) of 12.44 ± 2.69 L.min−1 under normoxia and 12.87 ± 2.56 L.min−1 under iso-saturation hypoxia.

measurementMales had a minute ventilation (VE) of 15.16 ± 2.47 L.min−1 under normoxia and 16.72 ± 3.64 L.min−1 under iso-saturation hypoxia.

measurementThe alpha index of low-frequency components (α–LF) for females was 10.0 ± 4.0 ms.mmHg−1 under normoxia and 6.7 ± 2.5 ms.mmHg−1 under iso-saturation hypoxia.

claimIn normoxia, females have smaller lung size and shape, as well as smaller luminal areas of large conducting airways, compared to males.

measurementFemales had a cardiac output of 6.99 ± 0.96 L.min−1 under normoxia and 7.46 ± 1.16 L.min−1 under iso-saturation hypoxia.

measurementMales had a cardiac output of 6.43 ± 0.76 L.min−1 under normoxia and 6.85 ± 0.91 L.min−1 under iso-saturation hypoxia.

measurementMales had a tidal volume (Vt) of 999 ± 180 ml under normoxia and 1,120 ± 206 ml under iso-saturation hypoxia.

measurementUnder normoxia, males have a tidal volume (Vt) of 999 ± 180 ml and females have 747 ± 125 ml; under iso-saturation hypoxia, males have 1,120 ± 206 ml and females have 753 ± 116 ml.

Sex differences in respiratory and circulatory cost during hypoxic ... nature.com Nature Jul 2, 2019 5 facts

claimThe estimated energy cost of circulation (HR) exceeded the energy cost of respiration (VE) in both normoxia and hypoxia conditions.

claimThere was no significant main effect for sex on oxygen saturation (SpO2) in either normoxia or hypoxia conditions.

measurementIn the study, no sex differences in SpO2 changes were found during walking in either normoxia or hypoxia, despite significant reductions in SpO2 observed in both groups.

measurementResting blood lactate concentration is similar across sexes in both normoxia (1.2 ± 0.2 mmol L−1 in men vs. 1.2 ± 0.2 mmol L−1 in women) and hypoxia (1.2 ± 0.2 mmol L−1 in men vs. 1.2 ± 0.3 mmol L−1 in women).

measurementIn normoxia, oxygen saturation (SpO2) decreased by approximately 3% from resting baselines in both men and women.