論文 - 片山　敬章

Ventilatory chemosensitive adaptations to intermittent hypoxic exposure with endurance training and detraining. 査読有り

Katayama, K., Y. Sato, Y. Morotome, N. Shima, K. Ishida, S. Mori, and M. Miyamura.

J. Appl. Physiol   86 巻   頁： 1805-1811   1999年

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The present study was performed to clarify the effects of intermittent exposure to an altitude of 4,500 m with endurance training and detraining on ventilatory chemosensitivity. Seven subjects (sea-level group) trained at sea level at 70% maximal oxygen uptake (VO2 max) for 30 min/day, 5 days/wk for 2 wk, whereas the other seven subjects (altitude group) trained at the same relative intensity (70% altitude VO2 max) in a hypobaric chamber. VO2 max, hypoxic ventilatory response (HVR), and hypercapnic ventilatory response, as an index of central hypercapnic chemosensitivity (HCVR) and as an index of peripheral chemosensitivity (HCVRSB), were measured. In both groups VO2 max increased significantly after training, and a significant loss of VO2 max occurred during 2 wk of detraining. HVR tended to increase in the altitude group but not significantly, whereas it decreased significantly in the sea-level group after training. HCVR and HCVRSB did not change in each group. After detraining, HVR returned to the pretraining level in both groups. These results suggest that ventilatory chemosensitivity to hypoxia is more variable by endurance training and detraining than that to hypercapnia.

Effects of maximal interval training on arterial oxygen desaturation and ventilation during heavy exercise

Motohiko Miyachi, Keisho Katayama

Japanese Journal of Physiology   49 巻 ( 5 ) 頁： 401 - 407   1999年

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：The Physiological Society of Japan  

The purpose of the present study was to clarify longitudinally the effects of exercise training on arterial O2 saturation (Sa(O)2) and ventilation during heavy exercise. A group of six subjects (training group) volunteered to train four times a week for 12 weeks. Each training session consisted of five 3-min periods of exercise on a cycle ergometer at a power output of 100% maximal O2 uptake (V̇O(2 max)), interspersed with 2 min recovery period cycling at 50% V̇O(2 max). During the training, V̇O(2 max), Sa(O)2, the ventilatory equivalent for oxygen (V̇E/V̇O2), and the end- tidal partial pressure of O2 (PET(O)2) during heavy exercise were measured periodically. The same parameters were measured simultaneously in another group of five subjects (control group) who led normal lives. Maximal interval training increases V̇O(2 max), with little change in V̇E(max) and pulmonary functions at rest. The training decreased PET(O)2, V̇E/V̇O2, and Sa(O)2 during heavy exercise. Sa(O)2 is significantly related to V̇E/V̇O2 (r2 = 0.49). These results suggest that less hyperventilatory response to exercise occurs with progress in physical training because the adaptability of ventilatory capacity is less than that of aerobic work capacity, which half induces arterial O2 desaturation during heavy exercise. PET(O)2 as well as V̇E/V̇O2 and V̇O(2 max) did not change anymore after the 6th week, nevertheless Sa(O)2 kept decreasing up to the last 2 weeks. In addition, when the Sa(O)2-V̇E/V̇O2 plot was compared between the two groups, the regression line of the training group was steeper than that of the control groups
i.e., compared at a lower level of V̇E/V̇O2 (~30 ml · ml-1), the Sa(O)2 of the trained subjects exercising at a higher V̇O2 level was lower than that of the control subjects. Predominance of less hyperventilation and another factor, increased A-aDO2, in the genesis of arterial hypoxemia and O2 desaturation may be dependent upon V̇O2 levels in heavy exercise and the state of training.

DOI： 10.2170/jjphysiol.49.401

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PubMed

The effects of intermittent exposure to hypoxia during endurance exercise training on the ventilatory responses to hypoxia and hypercapnia in humans 査読有り

Keisho Katayama, Yasutake Sato, Koji Ishida, Shigeo Mori, Miharu Miyamura

European Journal of Applied Physiology and Occupational Physiology   78 巻 ( 3 ) 頁： 189 - 194   1998年8月

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The present study was performed to investigate the effects of a combination of intermittent exposure to hypoxia during exercise training for short periods on ventilatory responses to hypoxia and hypercapnia (HVR and HCVR respectively) in humans. In a hypobaric chamber at a simulated altitude of 4500 m (barometric pressure 432 mmHg), seven subjects (training group) performed exercise training for 6 consecutive days (30 min·day-1), while six subjects (control group) were inactive during the same period. The HVR, HCVR and maximal oxygen uptake (V̇O(2max)) for each subject were measured at sea level before (pre) and after exposure to intermittent hypoxia. The post exposure test was carried out twice, i.e. on the 1st day and 1 week post exposure. It was found that HVR, as an index of peripheral chemosensitivity to hypoxia, was increased significantly (P &lt
0.05) in the control group after intermittent exposure to hypoxia. In contrast, there was no significant increase in HVR in the training group after exposure. The HCVR in both groups was not changed by intermittent exposure to hypoxia, while V̇O(2max) increased significantly in the training group. These results would suggest that endurance training during intermittent exposure to hypoxia depresses the increment of chemosensitivity to hypoxia, and that intermittent exposure to hypoxia in the presence or absence of exercise training does not induce an increase in the chemosensitivity to hypercapnia in humans.

DOI： 10.1007/s004210050406

Scopus

PubMed

The effects of intermittent exposure to hypoxia during endurance exercise training on the ventilatory responses to hypoxia and hypercapnia in humans. 査読有り

Katayama, K., Y. Sato, K. Ishida, S. Mori, and M. Miyamura.

Eur. J. Appl. Physiol.   78 巻   頁： 189-194   1998年

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The present study was performed to investigate the effects of a combination of intermittent exposure to hypoxia during exercise training for short periods on ventilatory responses to hypoxia and hypercapnia (HVR and HCVR respectively) in humans. In a hypobaric chamber at a simulated altitude of 4,500 m (barometric pressure 432 mmHg), seven subjects (training group) performed exercise training for 6 consecutive days (30 min x day(-1)), while six subjects (control group) were inactive during the same period. The HVR, HCVR and maximal oxygen uptake (VO2max) for each subject were measured at sea level before (pre) and after exposure to intermittent hypoxia. The post exposure test was carried out twice, i.e. on the 1st day and 1 week post exposure. It was found that HVR, as an index of peripheral chemosensitivity to hypoxia, was increased significantly (P < 0.05) in the control group after intermittent exposure to hypoxia. In contrast, there was no significant increase in HVR in the training group after exposure. The HCVR in both groups was not changed by intermittent exposure to hypoxia, while VO2max increased significantly in the training group. These results would suggest that endurance training during intermittent exposure to hypoxia depresses the increment of chemosensitivity to hypoxia, and that intermittent exposure to hypoxia in the presence or absence of exercise training does not induce an increase in the chemosensitivity to hypercapnia in humans.