Effect of two durations of short-term intermittent hypoxia on ventilatory chemosensitivity in humans.
The purpose of this study was to clarify the influence of duration of intermittent hypoxia per day on ventilatory chemosensitivity. Subjects were assigned to three different groups according to the duration of exposure to intermittent hypoxia (12.3 +/- 0.2% O(2)): a first group (H-1, n = 6) was exposed to hypoxia for 1 h per day, the second group (H-2, n = 6) was exposed for 3 h per day, and the third (C, n = 7) was used as control. Hypoxic and hypercapnic ventilatory responses (HVR and HCVR) were determined before and after 1 week of intermittent hypoxia. HVR was increased significantly (P < 0.05) after intermittent hypoxia in both the H-1 and H-2 groups. However, there was no significant difference in magnitude of increased HVR between H-1 and H-2 groups. HCVR did not show any changes in all groups after intermittent hypoxia. These results suggest that 1 h of daily exposure is as equally effective as 3 h of daily exposure to severe hypoxia for a short period for enhancing ventilatory chemosensitivity to hypoxia.
Katayama
Keisho
K
Research Center of Health, Physical Fitness and Sports, Graduate School of Education and Human Development, Nagoya University, Furocho, Chikusaku, Nagoya, 464-8601, Japan. katayama@htc.nagoya-u.ac.jp
Ishida
Koji
K
Iwasaki
Ken-Ichi
K
Miyamura
Miharu
M
D000222:Adaptation, Physiological; D000328:Adult; D006801:Humans; D000860:Hypoxia / Q000378:metabolism*; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D012123:Pulmonary Ventilation / Q000502:physiology*; D015656:Respiratory Mechanics