Effects of two and three weeks of tapering on lower respiratory tract in the maturing rat

Tapering is a method for improving the performance of athletes by reducing the risk factors produced by intense exercise. In this study, the effect of 2 to 3 weeks tapering followed by a 6 weeks of severe interval training was investigated on the lower respiratory tract remodeling in the maturing rat. 80 male rats within the age of 5 weeks were used in this study. After 6 weeks of intense interval training (IIT) (6 sessions per week for 30 min at speed of 15-70 m/min) rats were divided into 8 groups. Two IIT and control group were sacrificed at the beginning of the taper. Other 6 IIT groups were divided into repetition, frequency and intensity tapering for 2 and 3 weeks of interval performance. In the end, the animals were sacrificed and lungs were removed, weighed and sized. For histology, lungs were fixed in formalin and stained by H&E methods. Our results showed that the lung wet weight was increased in taper frequency group compared to IIT in the third week of exercise. Also taper exercise significantly reduced the longitude height of bronchial epithelial and thickness of tunica adventitia in taper groups compare to IIT group (P≤0.05). The reduction was larger in the third weeks of tapering than the second week. Taper training for three weeks reduced lower respiratory tract disorders caused by intense exercises in rats. Taper techniques may also have the same beneficial effects on the athletes’ respiratory system.