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Purpose: The Wingate anaerobic test measures the maximum anaerobic capacity of the lower limbs. The energy sources of Wingate test are dominated by anaerobic metabolism (~ 80%). Chronic high altitude exposure induces adaptations on skeletal muscle function and metabolism. Therefore, the study aim was to investigate possible changes in the energy system contribution to Wingate test before and after a high-altitude sojourn.Methods: Seven male climbers performed a Wingate test before and after a 43-day expedition in the Himalaya (23 days above 5.000 m). Mechanical parameters included: peak power (PP), average power (AP), minimum power (MP) and fatigue index (FI). The metabolic equivalents were calculated as aerobic contribution from O2 uptake during the 30-s exercise phase (WVO2), lactic and alactic anaerobic energy sources were determined from net lactate production (WLa) and the fast component of the kinetics of post-exercise oxygen uptake (WPCr), respectively. The total metabolic work (WTOT) was calculated as the sum of the three energy sources.Results: PP and AP decreased from 7.3 ± 1.1 to 6.7 ± 1.1 W/kg and from 5.9 ± 0.7 to 5.4 ± 0.8 W/kg, respectively, while FI was unchanged. WTOT declined from 103.9 ± 28.7 to 83.8 ± 17.8 kJ. Relative aerobic contribution remained unchanged (19.9 ± 4.8% vs 18.3 ± 2.3%), while anaerobic lactic and alactic contributions decreased from 48.3 ± 11.7 to 43.1 ± 8.9% and increased from 31.8 ± 14.5 to 38.6 ± 7.4%, respectively.Conclusion: Chronic high altitude exposure induced a reduction in both mechanical and metabolic parameters of Wingate test. The anaerobic alactic relative contribution increased while the anaerobic lactic decreased, leaving unaffected the overall relative anaerobic contribution to Wingate test. [ABSTRACT FROM AUTHOR]

Purpose: We investigated the effects of moderate-intensity training at low and high altitude on VO2 and QaO2 kinetics and on myosin heavy-chain expression (MyHC) in seven women (36.3 yy ± 7.1; 65.8 kg ± 11.7; 165 cm ± 8) who participated in two 12- to 14-day trekking expeditions at low (598 m) and high altitude (4132 m) separated by 4 months of recovery.Methods: Breath-by-breath VO2 and beat-by-beat QaO2 at the onset of moderate-intensity cycling exercise and energy cost of walking (Cw) were assessed before and after trekking. MyHC expression of vastus lateralis was evaluated before and after low-altitude and after high-altitude trekking; muscle fiber high-resolution respirography was performed at the beginning of the study and after high-altitude trekking.Results: Mean response time of VO2 kinetics was faster (P = 0.002 and P = 0.001) and oxygen deficit was smaller (P = 0.001 and P = 0.0004) after low- and high-altitude trekking, whereas ˙ QaO2 kinetics and Cw did not change. Percentages of slow and fast isoforms of MyHC and mitochondrial mass were not affected by low- and high-altitude training. After training altitude, muscle fiber ADP-stimulated mitochondrial respiration was decreased as compared with the control condition (P = 0.016), whereas leak respiration was increased (P = 0.031), leading to a significant increase in the respiratory control ratio (P = 0.016).Conclusions: Although training did not significantly modify muscle phenotype, it induced beneficial adaptations of the oxygen transport-utilization systems witnessed by faster VO2 kinetics at exercise onset. [ABSTRACT FROM AUTHOR]

Chronic hypoxia is related to many pathological conditions: aging, heart and respiratory failure, sleep apneas, smoke, chronic obstructive pulmonary disease (COPD), diabetes, hypertension and arteriosclerosis, all characterized by reductions of sleep-related erections (SREs) and by erectile dysfunction (ED). Sleep-related erections occur naturally during rapid eye movement (REM) sleep in sexually potent men. Hypoxia is also a physiological condition at altitude. The level of inspired oxygen decreases progressively with the increase of altitude; for this reason, this study was performed to evaluate the relationship of SREs with hypoxic environment. SREs have been recorded by an erectometer (RigiScan) on three mountain climbers (mean age: 32.5) during a 26-day stay at an altitude ranging from 2000 to 5600 m above sea level. Twenty-four records have been made at progressively increasing altitudes. A data analysis was carried out on a statistical mean of the three values of each variable and an analysis of variance (ANOVA) and Newman–Keuls test were carried out for multiple comparison among groups. At altitudes over 4450 m, we found lack of rigidity at 80–100% and 60–79%. Mean % of rigidity and rigidity time of 80–100% (tip and base) decreased progressively with altitude. No significant reductions were shown in rigidity time at 0–19% and at 20–39% (tip and base), of total number, of total and mean duration of SREs. Pathological rigidometric records at high altitude in sexually potent men at sea level clarify the primary role of hypoxia in physiopathological ED pathway.International Journal of Impotence Research (2007) 19, 496–500; doi:10.1038/sj.ijir.3901560; published online 31 May 2007 [ABSTRACT FROM AUTHOR]

This review summarises key aspects of the first reproductive and developmental systems Science Community White Paper, supported by the European Space Agency (ESA). Current knowledge regarding human development and reproduction in space is mapped to the roadmap. It acknowledges that sex and gender have implications on all physiological systems, however, gender identity falls outside the scope of the document included in the white paper collection supported by ESA. The ESA SciSpacE white papers on human developmental and reproductive functions in space aim to reflect on the implications of space travel on the male and female reproductive systems, including the hypothalamic-pituitary-gonadal (HPG) reproductive hormone axis, and considerations for conception, gestation and birth. Finally, parallels are drawn as to how this may impact society as a whole on Earth., (© 2023. The Author(s).)