Clinical and experimental pharmacology & physiology
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Clin. Exp. Pharmacol. Physiol. · Jan 2020
Effect of chronic intermittent hypobaric hypoxia on heart rate variability in conscious rats.
To examine the effect of chronic intermittent hypobaric hypoxia (CIHH) on heart rate variability (HRV), male adult Sprague Dawley rats were exposed to hypoxia (oxygen 11.1%) in a hypobaric chamber for 42 days, 6 hours each day, simulating an altitude of 5000 m. The body weight and blood pressure of rats were recorded once a week, electrocardiograms were analyzed continuously using biotelemetry, before, during and after CIHH treatment each day, and HRV was evaluated using spectrum analysis. No significant difference of body weight and blood pressure was found between CIHH and control rats. ⋯ In addition, the HR was increased in CIHH rats after 4 weeks of CIHH treatment compared with control rats. Furthermore, HRV was altered significantly in control rats, but not in CIHH rats exposed to acute normobaric hypoxia. These data suggest that CIHH treatment modulates cardiac autonomic activity adaptively and inhibits the acute normobaric hypoxia-induced changes in HRV.