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This study examined the associations of cardiorespiratory fitness (CRF) and leisuretime physical activity (LTPA) with health-related quality of life (HRQoL) P=.020).To conclude, CRF and LTPA were positively associated with perceived general health and physical well-being in women planning pregnancy and at risk for GDM. Even a slightly better CRF would be beneficial for well-being among women with low levels of CRF. K E Y W O R D Sfemale, maximal oxygen uptake, physical activity, quality of life, self-rated health

The magnitude and timing of oxygenation responses in highly active leg muscle, less active arm muscle, and cerebral tissue, have not been studied with simultaneous alveolar gas exchange measurement during incremental treadmill exercise. Nor is it known, if blood O 2 carrying capacity affects the tissue-specific oxygenation responses. Thus, we investigated alveolar gas exchange and tissue (m. vastus lateralis, m. biceps brachii, cerebral cortex) oxygenation during incremental treadmill exercise until volitional fatigue, and their associations with blood O 2 carrying capacity in 22 healthy men. Alveolar gas exchange was measured, and near-infrared spectroscopy (NIRS) was used to monitor relative concentration changes in oxy-( [O 2 Hb]), deoxy-( [HHb]) and total hemoglobin ( [tHb]), and tissue saturation index (TSI). NIRS inflection points (NIP), reflecting changes in tissue-specific oxygenation, were determined and their coincidence with ventilatory thresholds [anaerobic threshold (AT), respiratory compensation point (RC); V-slope method] was examined. Blood O 2 carrying capacity [total hemoglobin mass (tHb-mass)] was determined with the CO-rebreathing method. In all tissues, NIPs coincided with AT, whereas RC was followed by NIPs. High tHb-mass associated with leg muscle deoxygenation at peak exercise (e.g., [HHb] from baseline walking to peak exercise vs. tHb-mass: r = 0.64, p < 0.01), but not with arm muscle-or cerebral deoxygenation. In conclusion, regional tissue oxygenation was characterized by inflection points, and tissue oxygenation in relation to alveolar gas exchange during incremental treadmill exercise resembled previous findings made during incremental cycling. It was also found out, that O 2 delivery to less active m. biceps brachii may be limited by an accelerated increase in ventilation at high running intensities. In addition, high capacity for blood O 2 carrying was associated with a high level of m. vastus lateralis deoxygenation at peak exercise.

Blood O₂ carrying capacity affects aerobic capacity (VO₂max). Patients with type 1 diabetes have a risk for anaemia along with renal impairment, and they often have low VO₂max. We investigated whether total haemoglobin mass (tHb-mass) and blood volume (BV) differ in men with type 1 diabetes (T1D, n = 12) presently without complications and in healthy men (CON, n = 23) (age-, anthropometry-, physical activity-matched), to seek an explanation for low VO₂max. We determined tHb-mass, BV, haemoglobin concentration ([Hb]), and VO₂max in T1D and CON. With similar (mean ± SD) [Hb] (144 vs. 145 g l(-1)), T1D had lower tHb-mass (10.1 ± 1.4 vs. 11.0 ± 1.1 g kg(-1), P < 0.05), BV (76.8 ± 9.5 vs. 83.5 ± 8.3 ml kg(-1), P < 0.05) and VO₂max (35.4 ± 4.8 vs. 44.9 ± 7.5 ml kg(-1) min(-1), P < 0.001) than CON. VO₂max correlated with tHb-mass and BV both in T1D (r = 0.71, P < 0.01 and 0.67, P < 0.05, respectively) and CON (r = 0.54, P < 0.01 and 0.66, P < 0.001, respectively), but not with [Hb]. Linear regression slopes were shallower in T1D than CON both between VO₂max and tHb-mass (2.4 and 3.6 ml kg(-1) min(-1) vs. g kg(-1), respectively) and VO₂max and BV (0.3 and 0.6 ml kg(-1) min(-1) vs. g kg(-1), respectively), indicating that T1D were unable to reach similar VO₂max than CON at a given tHb-mass and BV. In conclusion, low tHb-mass and BV partly explained low VO₂max in T1D and may provide early and more sensitive markers of blood O₂ carrying capacity than [Hb] alone.

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