この研究の目的は，運動中において腹式呼吸による呼吸コントロールの有効性を明らかにすることである．対象は12名の健常男性とし，運動負荷は自転車エルゴメーターを用いて，Ramp負荷法によって最大酸素摂取量（maximum oxygen intake：Vo2max）の80％（80％Vo2max）まで施行した．実験条件は呼吸コントロールを行わない場合と，運動開始時から腹式呼吸を用いて呼吸コントロールを行った場合の２条件とした．呼吸代謝測定は呼気ガス分析器を用いて分時換気量（minute ventilation：VE）や体重あたりの酸素摂取量（oxygen intake/body weight：Vo2/BW），一回換気量（tidal volume：TV），呼吸数（respiratory rate：RR），心拍数（heart rate：HR）などの換気パラメータを測定した．その結果，運動中における腹式呼吸の効果としてVE減少やTV増加，RR減少が確認できた．また80％Vo2maxの運動負荷中において，運動初期にVEをはじめRR，HRの項目にCentral command説によると考えられる一時的な変化がみられた．運動時間70％以降の運動後半において，腹式呼吸によってVo2/BW増加とVE/Vo2減少という影響が出現していた．またＶ-slope法による無酸素性作業閾値（anaerobic threshold：AT）ポイントも，腹式呼吸により有意に高値を示しており，有酸素系エネルギーの供給が高められると考えらえた．

The objective of the present study was to investigate the effects of abdominal breathing on respiration and circulation during exercise, in order to clarify the effectiveness of respiratory control (in the form of abdominal breathing) during exercise. Subjects were 12 healthy men with a mean age of 22.3±3.3 years. Using a bicycle ergometer (Combi Aerobike 75XL) a ramp test was administered at 20 W/min to achieve 80% VO2max. One group of subjects (Group A, n=12used abdominal breathing as soon as the exercise started, while the other group (Controls, n=12) did not utilize respiratory control. Respiratory metabolism was assessed according to the breath-by-breath method using an expiration gas analyzer (SenserMedics Vmax29C. In the present study, ventilation parameters such as minute ventilation (VE), tidal volume (TV), respiratory rate (RR), heart rate (HR), oxygen uptake per body weight (VO2/BW), carbon dioxide uptake per body weight (VCO2/BW) and minute ventilation per oxygen uptake (VE/VO2) were measured. In addition, anaerobic threshold (AT) was calculated using the V-slope method and levels of lactic acid were measured before and after exercise to objectively determine exercise intensity. TV was higher in Group A than in Controls during exercise, while VE and RR were lower. In addition, at 80% VO2max, as explained by the central command theory, transient changes in VE, RR and HR were observed in the early stage. Levels of VO2/BW and VCO2/BW for Group A were also higher. In the late stage of exercise (final 30% of exercise time), VO2/BW for Group A was higher than for Controls, while VE/VO2 was lower. AT level, as measured using the V-slope method, was significantly higher in Group A than in Controls, suggesting that respiratory control increases the supply of aerobic energy.

長崎大学医学部保健学科紀要 = Bulletin of Nagasaki University School of Health Sciences. 2002, 15(2), p.63-68