Effects of prolonged low-frequency whole-body vibration on rats

Abstract

Two cages of rats (N = 10) were subjected to continuous low-frequency vibration for 92 days. The vibrated Ss weighed less than control Ss in the later stages of vibration and were more active in an open-field test given 3 days after the vibration period. Necropsies of both groups did not reveal any permanent damage to the heart, kidneys, spleen, lungs, brain, testes, adrenals, thymus~ and liver as a consequence of the prolonged vibration. H~man Ss exposed to low-frequency whole-body vibration in buildings, vehicles, and aircraft often report discomfort. The experimental research regarding the effects of vibration upon animals has been reviewed by Schaefer & Ulmer (1959) and Nadel (1963). Schaefer, Link, Farrar, & Weins (1959) showed that lethality in confined rats was directly related to the frequency (10 to 45 Hz) of whole-body vibration when the amplitude was held constant at 0.25 in. In further studies, Schaefer, Ulmer, & Link (1959) found that vibrated rats weighted less, were less active in an open field, and that some . Ss had testicular atrophy and myocardial hemorrhages. The authors jrter~reted these findings as ... demonstrating a general decrement or debility in both behavioral and physiological functioning, similar to the usual stress pattern [po 25]. Hunt & Quay ( 1961) and Soskin (1963) employed whole-body vibration to test Hebb's discrepancy-arousal theory of motivation. While their results generally did not confirm Hebb's theory, vibration was shown to be an effective aversive stimulus-Hunt and Quay demonstrated that naive rats woul d leverpress to terminate vibration, and Soskin observed that rats preferred a nonvibrating goalbox to a vibrating one in U-maze tests. It may be noted that the Ss were vibrated for 53 and 21 days, respectively, in the two studies prior to tests. More recently, in a series of seven experiments, Wike & Wike (1972) in v est igated barpressing that