Effect Of Resistance Training On Myocardial Contractility In Vitro After Sleep Deprivation

Abstract Background: Resistance training promotes cardiovascular health benefits that may affected by sleep deprivation. Objective: To evaluate the effect of high-intensity resistance training on myocardial contractility in rats subsequently subjected to paradoxical sleep deprivation. Methods: Forty male Wistar rats were distributed into control group (CTRL), resistance training (REST), 96-hour paradoxical sleep deprivation (PSD96) and resistance training followed by 96-hour paradoxical sleep deprivation (REST/PSD96). The animals underwent high-intensity resistance training for 8 weeks, 5x/week. Twenty-four hours after the last training session, the PSD96 and REST/PSD96 groups were submitted to paradoxical sleep deprivation, which was followed by the in vitro study of isolated papillary muscle contractile mechanics. Results: In comparison with the CTRL group, a lower papillary muscle length and increased cross sectional area were found in PSD96 and RETS/PSD96, which were associated with decreased temporal parameters of contraction force and relaxation. Decreased resting tension and slowing of relaxation time were found in the PSD96 group only. This effect was attenuated by previous resistance training. Conclusion: Resistance training partially prevented contractile changes induced by PSD, minimizing the slowing in relaxation time. Thus, high-intensity exercise seems to not fully protect the cardiac tissue from PSD-induced effects.