{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,3]],"date-time":"2026-10-03T17:33:33Z","timestamp":1791048813881,"version":"4.1.0"},"reference-count":42,"publisher":"American Physiological Society","issue":"3","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["American Journal of Physiology-Heart and Circulatory Physiology"],"published-print":{"date-parts":[[2005,3]]},"abstract":"<jats:p> We investigated whether dynamic cerebral autoregulation is affected by exhaustive exercise using transfer-function gain and phase shift between oscillations in mean arterial pressure (MAP) and middle cerebral artery (MCA) mean blood flow velocity ( V<jats:sub>mean<\/jats:sub>). Seven subjects were instrumented with a brachial artery catheter for measurement of MAP and determination of arterial Pco<jats:sub>2<\/jats:sub> (Pa<jats:sub>CO<jats:sub>2<\/jats:sub><\/jats:sub>) while jugular venous oxygen saturation (Sv<jats:sub>O<jats:sub>2<\/jats:sub><\/jats:sub>) was determined to assess changes in whole brain blood flow. After a 10-min resting period, the subjects performed dynamic leg-cycle ergometry at 168 \u00b1 5 W (mean \u00b1 SE) that was continued to exhaustion with a group average time of 26.8 \u00b1 5.8 min. Despite no significant change in MAP during exercise, MCA V<jats:sub>mean<\/jats:sub> decreased from 70.2 \u00b1 3.6 to 57.4 \u00b1 5.4 cm\/s, Sv<jats:sub>O<jats:sub>2<\/jats:sub><\/jats:sub> decreased from 68 \u00b1 1 to 58 \u00b1 2% at exhaustion, and both correlated to Pa<jats:sub>CO<jats:sub>2<\/jats:sub><\/jats:sub> (5.5 \u00b1 0.2 to 3.9 \u00b1 0.2 kPa; r = 0.47; P = 0.04 and r = 0.74; P &lt; 0.001, respectively). An effect on brain metabolism was indicated by a decrease in the cerebral metabolic ratio of O<jats:sub>2<\/jats:sub> to [glucose + one-half lactate] from 5.6 to 3.8 ( P &lt; 0.05). At the same time, the normalized low-frequency gain between MAP and MCA V<jats:sub>mean<\/jats:sub> was increased ( P &lt; 0.05), whereas the phase shift tended to decrease. These findings suggest that dynamic cerebral autoregulation was impaired by exhaustive exercise despite a hyperventilation-induced reduction in Pa<jats:sub>CO<jats:sub>2<\/jats:sub><\/jats:sub>. <\/jats:p>","DOI":"10.1152\/ajpheart.00948.2004","type":"journal-article","created":{"date-parts":[[2004,10,21]],"date-time":"2004-10-21T20:14:48Z","timestamp":1098389688000},"page":"H1461-H1467","source":"Crossref","is-referenced-by-count":126,"title":["Dynamic cerebral autoregulation during exhaustive exercise in humans"],"prefix":"10.1152","volume":"288","author":[{"given":"Shigehiko","family":"Ogoh","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mads K.","family":"Dalsgaard","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chie C.","family":"Yoshiga","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ellen A.","family":"Dawson","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David M.","family":"Keller","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peter B.","family":"Raven","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Niels H.","family":"Secher","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"24","reference":[{"key":"R1","doi-asserted-by":"publisher","DOI":"10.1161\/01.STR.20.1.45"},{"key":"R2","doi-asserted-by":"crossref","unstructured":"Bachmann C. 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