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Purpose: Exercise-induced arterial hypoxemia (EIAH) is reported to occur in approximately 50% of highly trained male endurance athletes. Few studies have examined EIAH in women and the prevalence remains unclear. It has been reported that some female subjects who develop EIAH possess maximal oxygen consumption (VO2max) values that are within 15% of their predicted value. This is unique to women, where EIAH has generally been reported in men who have a high VO2max. The primary objective of this investigation was to determine the prevalence of EIAH in a large female population with a wide range of VO2max values. It was hypothesized that EIAH would occur with a greater prevalence and at relatively lower predicted VO2max than that previously reported in males., Methods: Young women (N = 52; 26.5 +/- 4.9 yr) performed a cycle test to exhaustion to determine VO2max, and oxyhemoglobin saturation (SaO2) was monitored via pulse oximetry. All subjects were tested during the early follicular phase of their menstrual cycle. A >/= 4% drop in SaO2 represented EIAH., Results: Values for VO2max were variable (VO2max range: 28.0-61.3 mL x kg(-1) x min(-1)). EIAH was present in 67% of the women with N = 19 displaying mild EIAH (92-94%SaO2) and N = 16 displaying moderate EIAH (87-91%SaO2)., Conclusion: It appears that the prevalence of EIAH in women is slightly greater than the 50% prevalence value that is typically reported for highly fit men.

The article presents a study that investigated the theory that Epigallocatechin-3-gallate (EGCG) short-term consumption delays the ventilatory threshold (V T) onset and increases uptake of maximal oxygen (VO 2max). Nineteen healthy adults were given EGCG or placebo pills which they took before every exercise testing. VO 2max and V T were determined using the calorimetry data gathered during their exercise testing. Results revealed that short-term consumption of EGCG increased VO 2max and had no effect on maximal cardiac output. The study concludes that short-term EGCG consumption increased VO 2max but did not affect maximal cardiac output, which suggests that it may increase arterial-venous oxygen difference.

PURPOSE: To determine if electrolyte or carbohydrate supplementation vs. plain water would limit the magnitude of dehydration and decline in cognitive function in humans. METHODS: 24 subjects performed 3 visits consisting of 2hrs of walking at 3mph/7% grade in an environmental chamber set to 33ºC/10% RH. In random order, subjects consumed water (W), water+electrolyte (GZ), or water+electrolyte+sugar (G). Throughout exercise (EX), subjects carried a 23kg pack, and drank ad libitum. Pre and post EX, body mass (BM) and plasma osmolality (pOsm) were measured. Physiological Strain Index (PSI), an index of cardiovascular and thermal stress, and core temperature (TC) were recorded every 15mins. Plasma glucose (GLU) was measured every 30mins. Cognitive processing speed, measured via the Stroop Test (SCWT), was measured post EX and compared to baseline (BL). A subset of 8 subjects performed a normothermic (N) protocol (21ºC/ambient humidity) to ascertain how the exercise stimulus would influence hydration status and cognitive function in the absence of heat. RESULTS: There were no significant differences between fluid conditions (W, GZ, & G) for BM loss (Δ3.2±0.2, 3.1±0.2, & 3.0±0.3kg), fluid consumption (1.9±0.2, 1.9±0.2, & 1.8±0.2L), pOsm (Δ1.5±2.7, 2.2±2.4, & 2.0±1.5mmol/L), peak PSI (7.5±0.4, 7.0±0.6, & 7.9±0.5), and peak TC (38.7±0.1, 38.6±0.1, & 38.8±0.2ºC). Compared to W and GZ, GLU significantly increased from BL in the G condition (107±4 & 109±3mg/dL at 90 & 120mins, P<0.05). Compared to BL values, SCWT performance significantly decreased in all conditions (463±93, 422±83, & 140±52ms for W, GZ, & G, P<0.05). Importantly, compared to the W and GZ conditions, the SCWT performance was significantly attenuated in the G condition (P<0.05). As expected, when compared to the heat stress protocol (W, GZ, & G), the N condition resulted in lower BM loss, fluid consumption, and peak PSI (2.0±0.1kg, 1.2±0.7L, & 4.8, respectively). CONCLUSIONS: These data are the first to suggest that, independent of supplementation variety, cognitive processing significantly decreases immediately following long duration exercise in the heat in healthy humans. Compared to water and fluids supplemented with only electrolytes, fluids supplemented with carbohydrates significantly blunts this decrease in cognitive function. [ABSTRACT FROM AUTHOR]