Abstract
Cerebral blood flow (CBF) in humans was measured at rest and during dynamic exercise on a cycle ergometer corresponding to 56% (range 27-85) of maximal O2 uptake (VO2max). Exercise bouts were performed by 16 male and female subjects, lasted 15 min each, and were carried out in a semisupine position. CBF (133Xe clearance) was expressed as the initial slope index (ISI) and as the first compartment flow (F1). CBF at rest [ISI, 58 (range 45-73); F1, 76 (range 55-98) ml.100 g-1.min-1] increased during exercise [ISI to 79 (57-94) and F1 to 118 (75-164) ml.100 g-1.min-1, P less than 0.01]. CBF did not differ significantly between work loads from 32 (24-33) to 86% (74-96) of VO2max (n = 10). During exercise, mean arterial pressure increased from 84 (60-100) to 101 (78-124) Torr (P less than 0.01) and PCO2 remained unchanged [5.1 (4.6-5.6) vs. 5.4 (4.4-6.3) kPa, n = 6]. These results demonstrate a median increase of 31% (0-87) in CBF by ISI and a median increase of 58% (0-133) in CBF by F1 during dynamic exercise in humans.
| Original language | English |
|---|---|
| Journal | Journal of applied physiology (Bethesda, Md. : 1985) |
| Volume | 67 |
| Issue number | 2 |
| Pages (from-to) | 744-8 |
| Number of pages | 5 |
| ISSN | 8750-7587 |
| Publication status | Published - Aug 1989 |
| Externally published | Yes |
Keywords
- Adult
- Blood Flow Velocity
- Blood Pressure
- Carbon Dioxide
- Cerebrovascular Circulation
- Exercise
- Exercise Test
- Female
- Heart Rate
- Humans
- Male
- Oxygen Consumption
- Partial Pressure
- Respiration
- Tidal Volume