{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,31]],"date-time":"2026-07-31T15:10:26Z","timestamp":1785510626887,"version":"3.56.0"},"reference-count":66,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2021,6,28]],"date-time":"2021-06-28T00:00:00Z","timestamp":1624838400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Life"],"abstract":"<jats:p>Periodic breathing is a respiratory phenomenon frequently observed in patients with heart failure and in normal subjects sleeping at high altitude. However, until recently, periodic breathing has not been studied in wakefulness and during exercise. This review relates the latest findings describing this ventilatory disorder when a healthy subject is submitted to simultaneous physiological (exercise) and environmental (hypoxia, hyperoxia, hypercapnia) or pharmacological (acetazolamide) stimuli. Preliminary studies have unveiled fundamental physiological mechanisms related to the genesis of periodic breathing characterized by a shorter period than those observed in patients (11~12 vs. 30~60 s). A mathematical model of the respiratory system functioning under the aforementioned stressors corroborated these data and pointed out other parameters, such as dead space, later confirmed in further research protocols. Finally, a cardiorespiratory interdependence between ventilatory oscillations and heart rate variability in the low frequency band may partly explain the origin of the augmented sympathetic activation at exercise in hypoxia. These nonlinear instabilities highlight the intrinsic \u201chomeodynamic\u201d system that allows any living organism to adapt, to a certain extent, to permanent environmental and internal perturbations.<\/jats:p>","DOI":"10.3390\/life11070625","type":"journal-article","created":{"date-parts":[[2021,6,28]],"date-time":"2021-06-28T11:45:40Z","timestamp":1624880740000},"page":"625","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":14,"title":["Exercising in Hypoxia and Other Stimuli: Heart Rate Variability and Ventilatory Oscillations"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3925-3393","authenticated-orcid":false,"given":"Eric","family":"Hermand","sequence":"first","affiliation":[{"name":"ULR 7369-URePSSS-Unit\u00e9 de Recherche Pluridisciplinaire Sport Sant\u00e9 Soci\u00e9t\u00e9, Univ. Littoral C\u00f4te d\u2019Opale, Univ. Artois, Univ. Lille, 59379 Dunkerque, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1491-5896","authenticated-orcid":false,"given":"Fran\u00e7ois J.","family":"Lhuissier","sequence":"additional","affiliation":[{"name":"UMR INSERM U1272 Hypoxie & Poumon, Universit\u00e9 Sorbonne Paris Nord, 93017 Bobigny, France"},{"name":"M\u00e9decine de L\u2019Exercice et du Sport, Assistance Publique H\u00f4pitaux de Paris H\u00f4pital Jean Verdier, 93140 Bondy, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2772-9232","authenticated-orcid":false,"given":"Aur\u00e9lien","family":"Pichon","sequence":"additional","affiliation":[{"name":"Laboratoire MOVE (EA6314), Universit\u00e9 de Poitiers, 86073 Poitiers, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2092-4900","authenticated-orcid":false,"given":"Nicolas","family":"Voituron","sequence":"additional","affiliation":[{"name":"UMR INSERM U1272 Hypoxie & Poumon, Universit\u00e9 Sorbonne Paris Nord, 93017 Bobigny, France"},{"name":"D\u00e9partement STAPS, Universit\u00e9 Sorbonne Paris Nord, 93000 Bobigny, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jean-Paul","family":"Richalet","sequence":"additional","affiliation":[{"name":"UMR INSERM U1272 Hypoxie & Poumon, Universit\u00e9 Sorbonne Paris Nord, 93017 Bobigny, France"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,6,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Granero-Gallegos, A., Gonz\u00e1lez-Qu\u00edlez, A., Plews, D., and Carrasco-Poyatos, M. 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