Mij
Senior Member (Voting Rights)
Abstract
We tested the hypothesis that high oestrogen [E2] and progesterone [P] increase minute ventilation (V̇E) and work of breathing (WB) during hypoxic exercise in the midluteal (ML) compared to the early follicular (EF) phase of the menstrual cycle, and in post-menopausal females using or not using hormone replacement therapies (HRT; non-HRT).
Young (YF: n=11, 24±4y) and older females (OF non-HRT: n=10, 58±4y; HRT: n=7, 59±2y) completed pulmonary function and a graded cycle test to determine maximal oxygen consumption (V̇O2max: YF=51±6; OF non-HRT=45±10; HRT=35±8ml/kg/min).
On experimental days, serum [P] and [E2] were measured prior to insertion of gastric and oesophageal balloon catheters, and 5 min of cycling at 70% peak power (two trials ea. in normoxia and hypoxia, FIO2=0.15). Ribcage (RMRC) and abdominal (RMAB) respiratory muscle (RM) recruitment were determined with optoelectronic plethysmography.
OF were tested at any time, and YF were tested in the EF ([P]=1.1±1.6ng/ml, p<0.001; [E2]=197.7±134.8pg/ml, p=0.002) and ML phase ([P]=29.6±15.2ng/ml; [E2]=514.8±249.8pg/ml). EF and ML hypoxic exercise V̇E (EF=86±18; ML=90±21L/min, p=0.315), WB (EF=132±62; ML=123±56J/min, p=0.151) and RM recruitment (RMRC & RMAB=∆1±0%) were similar.
There was a moderate correlation between hypoxic exercise ∆V̇E/V̇O2 and ∆[P] (r=0.685, p=0.029). A significant interaction of condition and HRT was present in OF (hypoxic V̇E non-HRT=83.2±18.5, HRT=66.9±12.3L/min, p=0.006).
Our findings suggest high [P] increases V̇E relative to low [P] during hypoxic exercise in YF. Contrary to our hypothesis, in OF HRT use may blunt hypoxic V̇E.
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We tested the hypothesis that high oestrogen [E2] and progesterone [P] increase minute ventilation (V̇E) and work of breathing (WB) during hypoxic exercise in the midluteal (ML) compared to the early follicular (EF) phase of the menstrual cycle, and in post-menopausal females using or not using hormone replacement therapies (HRT; non-HRT).
Young (YF: n=11, 24±4y) and older females (OF non-HRT: n=10, 58±4y; HRT: n=7, 59±2y) completed pulmonary function and a graded cycle test to determine maximal oxygen consumption (V̇O2max: YF=51±6; OF non-HRT=45±10; HRT=35±8ml/kg/min).
On experimental days, serum [P] and [E2] were measured prior to insertion of gastric and oesophageal balloon catheters, and 5 min of cycling at 70% peak power (two trials ea. in normoxia and hypoxia, FIO2=0.15). Ribcage (RMRC) and abdominal (RMAB) respiratory muscle (RM) recruitment were determined with optoelectronic plethysmography.
OF were tested at any time, and YF were tested in the EF ([P]=1.1±1.6ng/ml, p<0.001; [E2]=197.7±134.8pg/ml, p=0.002) and ML phase ([P]=29.6±15.2ng/ml; [E2]=514.8±249.8pg/ml). EF and ML hypoxic exercise V̇E (EF=86±18; ML=90±21L/min, p=0.315), WB (EF=132±62; ML=123±56J/min, p=0.151) and RM recruitment (RMRC & RMAB=∆1±0%) were similar.
There was a moderate correlation between hypoxic exercise ∆V̇E/V̇O2 and ∆[P] (r=0.685, p=0.029). A significant interaction of condition and HRT was present in OF (hypoxic V̇E non-HRT=83.2±18.5, HRT=66.9±12.3L/min, p=0.006).
Our findings suggest high [P] increases V̇E relative to low [P] during hypoxic exercise in YF. Contrary to our hypothesis, in OF HRT use may blunt hypoxic V̇E.
LINK