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We investigated whether leg and arm skeletal muscle, and cerebral deoxygenation, differ during incremental cycling exercise in men and women, and if women's lower capacity to deliver O2 affects tissue deoxygenation. Men (n=10) compared to women (n=10), had greater cardiac output, which with greater hemoglobin concentration produced greater absolute (QaO2) and body size-adjusted oxygen delivery (QaO2i) at peak exercise. Despite women's lower peak QaO2, their leg muscle deoxygenation was similar at a given work rate and QaO2, but less than in men at peak exercise (Δtissue saturation index -27.1 ± 13.2% vs. -11.8 ± 5.7%, P0.01; Δ[deoxyhemoglobin] 15.03 ± 8.57 μM vs. 3.73 ± 3.98 μM, P0.001). At peak exercise, oxygen uptake was associated both with QaO2 and leg muscle deoxygenation (both P0.01). Arm muscle and cerebral deoxygenation did not differ between sexes at peak exercise. Thus, both high O2 delivery and severe active muscle deoxygenation are determinants of good exercise performance, and active muscle deoxygenation responses are regulated partly in a sex-specific manner with an influence of exercise capacity.

Obesity is associated with metabolic complications such as insulin-resistance, type 2 diabetes, dyslipidemia, hypertension and polycystic ovary syndrome. Obesity adversely impacts fecundability and IVF outcomes through a variety of mechanisms, however even modest weight loss can improve situation. Pregnancy may be a significant health risk for morbidly obese women (BMI over 40 kg/m2) and fertility treatments are not recommended before weight loss. The fertile age of women is limited, therefore an efficient treatment of obesity should be chosen. For morbid obesity bariatric surgery combined with lifestyle changes is more efficient treatment than conservative treatment alone. Weight loss is associated with significant improvement in many parameters of reproductive function, chance to get pregnant improves and gestational risks decrease.

In polycystic ovary syndrome (PCOS), cardiovascular risk is increased. Peak O2 uptake (Embedded Image) predicts the cardiovascular risk. We were the first to examine the contribution of systemic O2 delivery and arteriovenous O2 difference to Embedded Image in overweight and obese women with PCOS. Fifteen overweight or obese PCOS women and 15 age‐, anthropometry‐, and physical activity‐matched control women performed a maximal incremental cycling exercise test. Alveolar gas exchange (volume turbine and mass spectrometry), arterial O2 saturation (pulse oximetry), and cardiac output (CO) (impedance cardiography) were monitored. Hb concentration was determined. Arterial O2 content and arteriovenous O2 difference (C(a‐v)O2) (Fick equation) were calculated. Insulin resistance was evaluated by homeostasis model assessment (HOMA‐IR). PCOS women had lower Embedded Image than controls (40 ± 6 vs. 46 ± 5 mL/min/kg fat‐free mass [FFM], P = 0.011). Arterial O2 content was similarly maintained in the groups throughout the exercise test (P > 0.05). Linear regression analysis revealed a pronounced response of CO to increasing Embedded Image in PCOS women during the exercise test: A ∆CO/∆Embedded Image slope was steeper in PCOS women than in controls (β = 5.84 vs. β = 5.21, P = 0.004). Eventually, the groups attained similar peak CO and peak CO scaled to FFM (P > 0.05). Instead, C(a‐v)O2 at peak exercise was lower in PCOS women than in controls (13.2 ± 1.6 vs. 14.8 ± 2.4 mL O2/100 mL blood, P = 0.044). HOMA‐IR was similar in the groups (P > 0.05). The altered cardiorespiratory responses to exercise in overweight and obese PCOS women indicate that PCOS per se is associated with alterations in peripheral adjustments to exercise rather than with limitations of systemic O2 delivery., published version, peerReviewed