Journal of Applied Physiology, Vol 63, Issue 4 1335-1338, Copyright © 1987 by American Physiological Society
Control of local heat gain by vasomotor response of the hand
T. Nagasaka, M. Cabanac, K. Hirata and T. Nunomura
Department of Physiology, School of Medicine, Kanazawa University, Japan.
Finger blood flow (BF) was measured by venous occlusion plethysmography
using mercury-in-Silastic strain gauges during immersion of one hand in hot
water (raised by steps of 2 degrees C every 10 min from 35 to 43 degrees
C), the other being a control (kept immersed in water at 35 degrees C). The
measurements were made in three different thermal states on separate days:
1) cool-25 degrees C, 40% rh, esophageal temperature (Tes) = 36.64 +/- 0.10
degrees C; 2) warm-35 degrees C, 40% rh, Tes = 36.71 +/- 0.11 degrees C;
and 3) hot-35 degrees C, 80% rh with the legs immersed in water at 42
degrees C, Tes = 37.26 +/- 0.11 degrees C. When water temperature was
raised at 42 degrees C, Tes = 37.26 +/- 0.11 When water temperature was
raised to 39-41 degrees C in the warm state, finger BF in the hand heated
locally (BFw) decreased. When water temperature was raised to 43 degrees C,
however, BFw returned to the control value. In the hot state, Tes rose
steadily, reaching 37.90 +/- 0.12 degrees C at the end of the 50-min
sessions. BF in the control finger also increased gradually during the
session. BFw showed a tendency to decrease when water temperature was
raised to 39 degrees C, but the change was not greater than that observed
in the warm state. In the cool state, no such reduction in BFw was observed
when water temperature was raised to 39-41 degrees C. On the contrary, BFw
increased at water temperatures of 41-43 degrees C.(ABSTRACT TRUNCATED AT
250 WORDS)
