Muscular strength capacity and altitude response

To determine the relationship between muscular strength and altitude response, two groups of 7 and 8 subjects were selected from 40 healthy male volunteers, as either high-strength (HS) or low-strength (LS) by performance on a battery of strength tests. There was no difference in hypoxic ventilatory response (HVR) between groups at normobaria. The 4 h hypobaric conditions in a Hypo-hyperbaric Chamber (PBar = 429) produced qualitatively similar altitude-induced physiological responses. However, the LS group showed a lower SaO2 at 2 and 4 h of hypoxia (p < 0.05). Furthermore, PETCO2 and PVCO2 were lower and PETO2, PVO2, and pH were greater in the HS group during hypobaria, although these differences did not achieve statistical significance. Muscular strength index (body weight divided by strength test values) was negatively correlated with PvCO2 (r = -0.63, p = 0.0074), PETCO2 (r = -0.62, p = 0.006) and positively with SaO2 (r = 0.54, p = 0.018) at altitude. These findings suggest that the HS group may have become more hypocapnic and alkalotic (suggesting a greater ventilatory response), and consequently less hypoxic than the LS group.