Sage Journals: Discover world-class research

Abstract

Conduction velocity, absolute refractory period, and subnormal conduction period measures of the right ulnar motor nerve were obtained during a simple reaction time task. 6 young, healthy, right-arm dominant male subjects were tested following 30 min. exposure in ambient (20°C) and hot (36°C) room air conditions. Motor and premotor components of fractionated reaction time were tested on the same arm. Oral, right forearm skin and a four-site mean skin temperature were monitored. During heat exposure, forearm skin temperature increased 4.7°C and mean skin temperature 2.9°C. Oral temperature did not alter. Conduction velocity increased 11.4%, absolute refractory period decreased 22.7%, and subnormal conduction period decreased 14.1% in the hot condition. Concomitantly, a 5.2% increase in premotor reaction time and 12.2% decrease in motor reaction time were observed. Total RT did not alter significantly. It was concluded that different component parts of reaction time were differentially influenced by exposure to heat.

Get full access to this article

View all access options for this article.

References

Baum

Bruck

Schwennicke

H. P.

Adaptive modifications in the thermoregulatory system of long-distance runners. Journal of Applied Physiology, 1979, 40, 404–410.

Bell

P. A.

Physiological, comfort, performance, and social effects of heat stress. Journal of Social Issues, 1981, 37, 71–93.

Courtright

J. F.

Effects of whole and partial body exposure to dry heat effects on certain performance measures. (Doctoral dissertation, Purdue Univer., 1976)

Dissertation Abstracts International, 1977, 37(8), 4201-B. (University Microfilms No. 77-1700, 304)

de Jesus

P. V.

Hausmanowa-Petrusewicz

Barchi

R. L.

The effect of cold on nerve conduction of human slow and fast nerve fibers. Neurology, 1973, 23, 1182–1189.

Delbeke

Kopec

McComas

A. J.

Effects of age, temperature, and disease on the refractoriness of human nerve and muscle. Journal of Neurology, Neurosurgery and Psychiatry, 1978, 41, 65–71.

Faisst

Meyer

A non-invasive computerized measurement of motor neurone refractory period and subnormal conduction in man. Electroencephalography and Clinical Neurophysiology, 1981, 51, 548–558.

Folk

G. E.

Jr.

Environmental physiology. (2nd ed.) Philadelphia: Lea & Febiger, 1974.

Hancock

P. A.

Dirkin

G. R.

Byrne

A. M.

Visual choice reaction time under conditions of induced cortical hyperthemia. Proceedings of the 14th Annual Meeting of the Human Factors Association of Canada, 1981. Pp. 15–18.

Holt

W. R.

Brainard

E. C.

Selective hyperthermia and reaction time. Perceptual and Motor Skills, 1976, 43, 375–382.

10.

Kimura

A method for estimating the refractory period of motor fibres in the human peripheral nerve. Journal of the Neurological Sciences, 1976, 28, 485–490.

11.

Leibowitz

H. W.

Abernethy

C. N.

Boskirk

E. R.

Bar-Or

Hennessy

R. T.

The effect of heat stress on reaction time to centrally and peripherally oriented stimuli. Human Factors, 1972, 14, 155–160.

12.

Shvartz

Meroz

Mechtinger

Birnfeld

Simple reaction time during exercise, heat exposure, and heat acclimation. Aviation, Space, and Environmental Medicine, 1976, 47, 1168–1170.

13.

Trnkoczy

Functional electrical stimulation of extremities: its basis, technology and role in rehabilitation. Automedica, 1978, 2, 59–100.

14.

Wood

G. A.

Electrophysiological correlates of local muscular fatigue effects upon human visual reaction time. European Journal of Applied Physiology, 1979, 41, 247–257.

Heat Exposure-Induced Changes in Motor Outflow Component of Reaction Time

Abstract

Get full access to this article

References