scholarly journals Sex differences in the cardiovascular consequences of the inspiratory muscle metaboreflex

2016 ◽  
Vol 311 (3) ◽  
pp. R574-R581 ◽  
Author(s):  
Joshua R. Smith ◽  
Ryan M. Broxterman ◽  
Shane M. Hammer ◽  
Andrew M. Alexander ◽  
Kaylin D. Didier ◽  
...  
Keyword(s):  
Sex Differences ◽  
Premenopausal Women ◽  
Inspiratory Muscle ◽  
Breathing Frequency ◽  
Limb Blood Flow ◽  
Men And Women ◽  
Muscle Metaboreflex ◽  
Healthy Men ◽  
Mouth Pressure ◽  
Resistive Breathing

It is currently unknown whether sex differences exist in the cardiovascular consequences of the inspiratory muscle metaboreflex. We hypothesized that the activation of the inspiratory muscle metaboreflex will lead to less of an increase in mean arterial pressure (MAP) and limb vascular resistance (LVR) and less of a decrease in limb blood flow (Q̇L) in women compared with men. Twenty healthy men ( n = 10, 23 ± 2 yr) and women ( n = 10, 22 ± 3 yr) were recruited for this study. Subjects performed inspiratory resistive breathing tasks (IRBTs) at 2% or 65% of their maximal inspiratory mouth pressure (PIMAX). During the IRBTs, the breathing frequency was 20 breaths/min with a 50% duty cycle. At rest and during the IRBTs, MAP was measured via automated oscillometry, Q̇L was measured via Doppler ultrasound, and LVR was calculated. EMG was recorded on the leg to ensure no muscle contraction occurred. The 65% IRBT led to attenuated increases ( P < 0.01) from baseline in women compared with men for MAP (W: 7.3 ± 2.0 mmHg; M: 11.1 ± 5.0 mmHg) and LVR (W: 17.7% ± 14.0%; M: 47.9 ± 21.0%), as well as less of a decrease ( P < 0.01) in Q̇L (W: −7.5 ± 9.9%; M: −23.3 ± 10.2%). These sex differences in MAP, Q̇L, and LVR were still present in a subset of subjects matched for PIMAX. The 2% IRBT resulted in no significant changes in MAP, Q̇L, or LVR across time or between men and women. These data indicate premenopausal women exhibit an attenuated inspiratory muscle metaboreflex compared with age-matched men.

scholarly journals Cardiovascular consequences of the inspiratory muscle metaboreflex: effects of age and sex

2017 ◽  
Vol 312 (5) ◽  
pp. H1013-H1020 ◽  
Author(s):  
Joshua R. Smith ◽  
Andrew M. Alexander ◽  
Shane M. Hammer ◽  
Kaylin D. Didier ◽  
Stephanie P. Kurti ◽  
...  
Keyword(s):  
Older Adults ◽  
Sex Differences ◽  
Older Women ◽  
Young Men ◽  
Premenopausal Women ◽  
Older Men ◽  
Inspiratory Muscle ◽  
Muscle Metaboreflex ◽  
Resistive Breathing ◽  
Younger Men

With inspiratory muscle metaboreflex activation, we hypothesized that, compared with their younger counterparts, older men and women would exhibit greater 1) increases in mean arterial pressure (MAP) and limb vascular resistance (LVR) and 2) decreases in limb blood flow (Q̇L) but 3) no sex differences would be present in older adults. Sixteen young adults [8 young men (YM) and 8 young women (YW), 18–24 yr] and 16 older adults [8 older men (OM) and 8 older women (OW), 60–73 yr] performed inspiratory resistive breathing tasks (IRBTs) at 2% and 65% of their maximal inspiratory pressure. During the IRBTs, breathing frequency was 20 breaths/min with a 50% duty cycle. At baseline and during the IRBTs, MAP was measured via automated oscillometry, Q̇L was determined via Doppler ultrasound, and LVR was calculated. The 65% IRBT led to significantly greater increases in MAP in OW (15.9 ± 8.1 mmHg) compared with YW (6.9 ± 1.4 mmHg) but not ( P > 0.05) between OM (12.3 ± 5.7 mmHg) and YM (10.8 ± 5.7 mmHg). OW (−20.2 ± 7.2%) had greater ( P < 0.05) decreases in Q̇L compared with YW (−9.4 ± 10.2%), but no significant differences were present between OM (−22.8 ± 9.7%) and YM (−22.7 ± 11.3%) during the 65% IRBT. The 65% IRBT led to greater ( P < 0.05) increases in LVR in OW (48.2 ± 25.5%) compared with YW (19.7 ± 15.0%), but no differences ( P > 0.05) existed among OM (54.4 ± 17.8%) and YM (47.1 ± 23.3%). No significant differences were present in MAP, Q̇L, or LVR between OM and OW. These data suggest that OW exhibit a greater inspiratory muscle metaboreflex compared with YW, whereas no differences between OM and YM existed. Finally, sex differences in the inspiratory muscle metaboreflex are not present in older adults. NEW & NOTEWORTHY Premenopausal women exhibit an attenuated inspiratory muscle metaboreflex compared with young men; however, it is unknown whether these sex differences are present in older adults. Older women exhibited a greater inspiratory muscle metaboreflex compared with premenopausal women, whereas no differences were present between older and younger men.

scholarly journals Effect of diaphragm fatigue on subsequent exercise tolerance in healthy men and women

2018 ◽  
Vol 125 (6) ◽  
pp. 1987-1996 ◽  
Author(s):  
Joseph F. Welch ◽  
Bruno Archiza ◽  
Jordan A. Guenette ◽  
Christopher R. West ◽  
A. William Sheel
Keyword(s):  
Exercise Test ◽  
Exercise Tolerance ◽  
Inspiratory Muscle ◽  
Whole Body ◽  
Time To Exhaustion ◽  
Men And Women ◽  
Muscle Metaboreflex ◽  
Healthy Men ◽  
Pressure Threshold ◽  
Diaphragmatic Fatigue

Women are more resistant to diaphragmatic fatigue (DF) and experience an attenuated inspiratory muscle metaboreflex relative to men. The effects of such sex-based differences on whole body exercise tolerance are yet to be examined. It was hypothesized that DF induced prior to exercise would cause less of a reduction in subsequent exercise time in women compared to men. Healthy men ( n = 9, age = 24 ± 3 yr) and women ( n = 9, age = 24 ± 3 yr) completed a maximal incremental cycle test on day 1. On day 2, subjects performed isocapnic inspiratory pressure-threshold loading (PTL) to task failure followed by a constant load submaximal time-to-exhaustion (TTE) exercise test at 85% of the predetermined peak work rate. On day 3, subjects performed the same exercise test without prior induced DF. Days 2 and 3 were randomized and counterbalanced. Magnetic stimulation of the phrenic nerve roots was used to nonvolitionally assess DF by measurement of transdiaphragmatic twitch pressure ( Pdi,tw). A similar degree of DF was produced in both sexes following PTL [ Pdi,tw (% change from baseline): M = −24.6 ± 7.8%, W = −23.1 ± 5.4%; P = 0.54)]. There was a significant reduction in TTE with prior induced DF compared with the control condition in both men (10.9 ± 3.5 min vs. 13.0 ± 3.2 min, P = 0.05) and women (10.1 ± 2.4 min vs. 12.2 ± 3.3 min, P = 0.03) that did not differ in magnitude between the sexes (M = −15.8 ± 19.5%, W = −14.5 ± 19.2%, P = 0.89). In conclusion, DF negatively and equally impairs exercise tolerance independent of sex. NEW & NOTEWORTHY Women are more resistant to diaphragmatic fatigue (DF) relative to men. The effect of DF on exercise tolerance is currently being debated. Our findings show that DF negatively and equally affects exercise tolerance in healthy men and women. Mechanisms beyond the inspiratory muscle metaboreflex (e.g., dyspnea, central fatigue, breathing pattern) may explain the absence of a sex-based difference.

Effect of Age on Sex Differences in the Inspiratory Muscle Metaboreflex

2017 ◽  
Vol 49 (5S) ◽  
pp. 796
Author(s):  
Joshua R. Smith ◽  
Andrew M. Alexander ◽  
Shane M. Hammer ◽  
Kaylin D. Didier ◽  
Stephanie P. Kurti ◽  
...  
Keyword(s):  
Sex Differences ◽  
Inspiratory Muscle ◽  
Muscle Metaboreflex ◽  
Effect Of Age

Sex Differences in the Inspiratory Muscle Metaboreflex

2016 ◽  
Vol 48 ◽  
pp. 670
Author(s):  
Joshua R. Smith ◽  
Ryan M. Broxterman ◽  
Shane M. Hammer ◽  
Andrew M. Alexander ◽  
Kaylin D. Didier ◽  
...  
Keyword(s):  
Sex Differences ◽  
Inspiratory Muscle ◽  
Muscle Metaboreflex

Are there sex differences in visceral sensitivity in young healthy men and women?

2019 ◽  
Vol 31 (9) ◽  
Author(s):  
Adriane Icenhour ◽  
Franziska Labrenz ◽  
Till Roderigo ◽  
Carsten Siebert ◽  
Sigrid Elsenbruch ◽  
...  
Keyword(s):  
Sex Differences ◽  
Visceral Sensitivity ◽  
Men And Women ◽  
Healthy Men

scholarly journals Diaphragm fatigue and inspiratory muscle metaboreflex in men and women matched for absolute diaphragmatic work during pressure‐threshold loading

2019 ◽  
Vol 597 (18) ◽  
pp. 4797-4808 ◽  
Author(s):  
Caitlin M. Geary ◽  
Joseph F. Welch ◽  
Malcolm R. McDonald ◽  
Carli M. Peters ◽  
Michael G. Leahy ◽  
...  
Keyword(s):  
Inspiratory Muscle ◽  
Men And Women ◽  
Muscle Metaboreflex ◽  
Pressure Threshold ◽  
Diaphragm Fatigue

scholarly journals Effect of cyclooxygenase inhibition on the inspiratory muscle metaboreflex-induced cardiovascular consequences in men

2017 ◽  
Vol 123 (1) ◽  
pp. 197-204 ◽  
Author(s):  
Joshua R. Smith ◽  
Kaylin D. Didier ◽  
Shane M. Hammer ◽  
Andrew M. Alexander ◽  
Stephanie P. Kurti ◽  
...  
Keyword(s):  
Vascular Resistance ◽  
Sympathetic Nerve Activity ◽  
Muscle Sympathetic Nerve Activity ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Inspiratory Muscle ◽  
Maximal Inspiratory Pressure ◽  
Muscle Metaboreflex ◽  
Resistive Breathing ◽  
Prostaglandin F

Inspiratory muscle metaboreflex activation increases mean arterial pressure (MAP) and limb vascular resistance (LVR) and decreases limb blood flow (Q̇L). Cyclooxygenase (COX) inhibition has been found to attenuate limb skeletal muscle metaboreflex-induced increases in muscle sympathetic nerve activity. We hypothesized that compared with placebo (PLA), COX inhibition would attenuate inspiratory muscle metaboreflex-induced 1) increases in MAP and LVR and 2) decreases in Q̇L. Seven men (22 ± 1 yr) were recruited and orally consumed ibuprofen (IB; 10 mg/kg) or PLA 90 min before performing the cold pressor test (CPT) for 2 min and inspiratory resistive breathing task (IRBT) for 14.9 ± 2.0 min at 65% of maximal inspiratory pressure. Breathing frequency was 20 breaths/min with a 50% duty cycle during the IRBTs. MAP was measured via automated oscillometry, Q̇L was determined via Doppler ultrasound, and LVR was calculated as MAP divided by Q̇L. Electromyography was recorded on the leg to ensure no muscle contraction occurred. The 65% IRBT led to greater increases ( P = 0.02) in 6-keto-prostaglandin-F1α with PLA compared with IB. IB, compared with PLA, led to greater ( P < 0.01) increases in MAP (IB: 17 ± 7 mmHg vs. PLA: 8 ± 5 mmHg) and LVR (IB: 69 ± 28% vs. PLA: 52 ± 22%) at the final minute of the 65% IRBT. The decrease in Q̇L was not different ( P = 0.72) between IB (−28 ± 11%) and PLA (−27 ± 9%) at the final minute. The increase in MAP during the CPT was not different ( P = 0.87) between IB (25 ± 11 mmHg) and PLA (24 ± 6 mmHg). Contrary to our hypotheses, COX inhibition led to greater inspiratory muscle metaboreflex-induced increases in MAP and LVR. NEW & NOTEWORTHY Cyclooxygenase (COX) products play a role in activating the muscle metaboreflex. It is not known whether COX products contribute to the inspiratory muscle metaboreflex. Herein, we demonstrate that COX inhibition led to greater increases in blood pressure and limb vascular resistance compared with placebo during inspiratory muscle metaboreflex activation.

Threshold of airway response to inhaled methacholine in healthy men and women

1984 ◽  
Vol 56 (1) ◽  
pp. 129-132 ◽  
Author(s):  
N. Zamel
Keyword(s):  
Sex Differences ◽  
Age Distribution ◽  
Flow Volume ◽  
Men And Women ◽  
Healthy Men ◽  
Doubling Dose ◽  
Full Inspiration ◽  
Airway Response

Threshold of airway response to inhaled methacholine was determined using maximum expiratory partial flow-volume curves in 21 men and 36 women with similar age distribution, all of them healthy nonsmokers. Mean threshold was on average 1.3 doubling dose lower in women than men. There were no sex differences in the increase of maximum expiratory flows after a full inspiration when the airways were constricted by methacholine.

scholarly journals Directional sensitivity of the cerebral pressure-flow relationship in middle and posterior cerebral arteries using the repeated squat-stand model: within-day reproducibility and impact of diurnal variation in young healthy men and women

2021 ◽  
Author(s):  
Lawrence Labrecque ◽  
Joel S. Burma ◽  
Marc-Antoine Roy ◽  
Jonathan D. Smirl ◽  
Patrice Brassard
Keyword(s):  
Sex Differences ◽  
Diurnal Variation ◽  
Cerebral Arteries ◽  
Intraclass Correlation ◽  
Time Of Day ◽  
Directional Sensitivity ◽  
Pressure Flow ◽  
Men And Women ◽  
Healthy Men ◽  
Time Points

We recently employed repeated squat-stands (RSS) to quantify directional sensitivity of the cerebral-pressure flow relationship (i.e. hysteresis) using a novel metric. Within-day reproducibility and diurnal variation impacts of this metric are unknown. We evaluated this metric for: 1) within-day reproducibility and the extent diurnal variation has in middle (MCA; ∆MCAvT/∆MAPT) and posterior cerebral arteries (PCA; ∆PCAvT/∆MAPT); 2) sex differences. Absolute (∆MCAvT/∆MAPT ; ∆PCAvT/∆MAPT) and relative (%MCAvT/%MAPT, %PCAvT/%MAPT) metrics were calculated at seven time-points (08:00-17:00) in 18 participants (8 women; 24 ± 3 yrs) using the minimum-to-maximum MCAv/PCAv and MAP for each RSS at 0.05 Hz and 0.10 Hz. Reproducibility was evaluated with intraclass correlation coefficient (ICC). For all metrics, reproducibility was good (0.75-0.90) to excellent (>0.90). The metric in both arteries was impacted by MAP direction at 0.10 Hz (all p < 0.024). Time-of-day influenced ∆MCAvT/∆MAPT (0.05 Hz: p = 0.0028; 0.10 Hz: p = 0.0009), %MCAvT/%MAPT (0.05 Hz: p = 0.035; 0.10 Hz: p = 0.0087), and ∆PCAvT/∆MAPT (0.05 Hz: p = 0.0236). Sex differences in the MCA (p = 0.0028) vanished in relative terms and was absent in the PCA. These findings demonstrate within-day reproducibility of this metric in both arteries. Moreover, hysteresis is not impacted by sex.

SEX DIFFERENCES BETWEEN HEALTHY MEN AND WOMEN IN PITUITARY LH-RESPONSE TO MULTIPLE STIMULATIONS WITH SYNTHETIC LH-RH

1975 ◽  
Vol 80 (1_Suppla) ◽  
pp. S22
Author(s):  
A. Römmler ◽  
S. Baumgarten ◽  
J. Hammerstein
Keyword(s):  
Sex Differences ◽  
Men And Women ◽  
Healthy Men ◽  
Lh Rh
Sign in / Sign up

Export Citation Format

Share Document