Changes in carotid blood flow and electrocardiogram in humans during and after walking on a treadmill.

European journal of applied physiology and occupational physiology

PubMedID: 8149926

He J, Jiang ZL, Tanaka H, Ikehara T, Takahashi A, Yamaguchi H, Miyamoto H, Iritani T, Kinouchi Y. Changes in carotid blood flow and electrocardiogram in humans during and after walking on a treadmill. Eur J Appl Physiol Occup Physiol. 1994;67(6):486-91.
Blood flow velocity in the common carotid artery and the electrocardiogram were measured simultaneously by telemetry in seven male subjects during 20-min walking on a treadmill at an exercise intensity corresponding to a mean oxygen uptake of 26. 0 (SD 2. 9) ml. kg-1. min-1. The mean cardiac cycle was shortened from 0. 814 (SD 0. 103) s to 0. 452 (SD 0. 054) s during this exercise. Of this shortening, 73% was due to shortening of the diastolic period and 27% to shortening of the systolic period. In the relatively small shortening of the mean systolic period [from 0. 377 (SD 0. 043) s to 0. 268 (SD 0. 029) s], the isovolumetric contraction time was shortened by 56%. During exercise, the heart rate (fc) increased by 79. 4% [from 74. 3 (SD 9. 3) beats. min-1 to 133. 3 (SD 14. 8) beats. min-1], and the peak blood velocity (S1) in the common carotid artery increased by 56. 1% [from 0. 82 (SD 0. 10) m. s-1 to 1. 28 (SD 0. 11) m. s-1]. After exercise, the S1 decreased rapidly to the resting level. The fc decreased more slowly, still being higher than the initial resting level 5 min after exercise. The diastolic velocity wave and the end-diastolic foot decreased during exercise. The blood flow rate in the carotid artery increased transiently by 13. 5% at the beginning of exercise [from 5. 62 (SD 0. 63) ml. s-1 to 6. 38 (SD 0. 85) ml. s-1] and by 26. 5% at the end of the exercise period [from 5. 62 (SD 0. 63) ml. s-1 to 7. 11 (SD 1. 34) ml. s-1]. (ABSTRACT TRUNCATED AT 250 WORDS).