{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,21]],"date-time":"2026-07-21T22:34:47Z","timestamp":1784673287010,"version":"3.55.0"},"reference-count":31,"publisher":"Oxford University Press (OUP)","issue":"5","license":[{"start":{"date-parts":[[2001,4,1]],"date-time":"2001-04-01T00:00:00Z","timestamp":986083200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/pages\/standard-publication-reuse-rights"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2001,4,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>We previously observed an increase in minute ventilation (V\u02d9e) with resistive unloading (He-O2 breathing) in healthy elderly subjects with normal pulmonary function. To investigate the effects of resistive unloading in elderly subjects with mild chronic airflow limitation (FEV1\/ FVC: 61 \u00b1 4%), we studied 10 elderly men and women 70 \u00b1 3 yr of age. These subjects performed graded cycle ergometry to exhaustion, once breathing room air and once breathing a He-O2 gas mixture (79% He, 21% O2). V\u02d9e, pulmonary mechanics, and PetCO2 were measured during each 1-min increment in work rate. Data were analyzed by paired t test at rest, at ventilatory threshold (VTh), and during maximal exercise. V\u02d9e was significantly (p &amp;lt; 0.05) increased at VTh (3.4 \u00b1 4.0 L \/ min or 12 \u00b1 15% increase) and maximal exercise (15.2 \u00b1 9.7 L \/ min or 22 \u00b1 13% increase) while breathing He-O2. Concomitant to the increase in V\u02d9e, PetCO2 was decreased at all levels (p &amp;lt; 0.01), whereas total work of breathing against the lung was not different. We concluded that V\u02d9e is increased during He-O2 breathing because of resistive unloading of the airways and the maintenance of the relationship between the work of breathing and exercise work rate.<\/jats:p>","DOI":"10.1164\/ajrccm.163.5.9908025","type":"journal-article","created":{"date-parts":[[2013,4,4]],"date-time":"2013-04-04T14:37:03Z","timestamp":1365086223000},"page":"1128-1134","source":"Crossref","is-referenced-by-count":26,"title":["Breathing He-O2 Increases Ventilation but Does Not Decrease the Work of Breathing during Exercise"],"prefix":"10.1093","volume":"163","author":[{"given":"T. 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