Temporary threshold shift induced by physical exercise

Several studies have demonstrated how physical exercise can increase noise-induced temporary threshold shifts (TTS), but until now no evidence of TTS exclusively attributable to physical activity has yet been reported. In this study the hearing pure-tone thresholds of 10 subjects were evaluated at rest and at three designated times following the end of a work load corresponding to 50% and 80% of the maximum oxygen uptake (VO2 max). The results obtained demonstrate a definite effect of physical exercise on the hearing threshold at 6000 and 8000 Hz and that the higher the frequency, the greater the chance of detecting a TTS. Evaluation of the variations in some physiologic parameters (VO2 max, blood lactate and blood pressure) could not statistically correlate the same with TTS. The physiopathologic mechanisms responsible for TTS are still unknown and require further studies which should make allowances for the deferred effects of metabolic variations on the cochlear function.