National Women Distance Runners Cardiac Function In Hypoxic Training

Objective: The research took the national female middle and long distance elite runners as the subjects. We attempted to investigate the effects of 4-week hypoxic training (HiHiLo and LoHi training) on cardiac function, we hoped to provide a reference for the development of hypoxic training.Methods: Thirteen national female middle and long distance runners were divided into HiHiLo group and LoHi group randomly. Both groups carried out HiHiLo and LoHi training program respectively. Training time was 4 weeks. CK-MB in blood serum and∑T/R on cardiogram were measured during hypoxic training. Cardiac Functions were monitored with Doppler echocardiography under load before and after Hypoxic Training. VO2max, blood pressure and bodyweight were measured before and after Hypoxic Training.Result: 1. With the progression of hypoxic training, the value of CK-MB showed a decreasing tendency as compared with that before hypoxic exposure in HiHiLo group, it significantly decreased after 4-week hypoxic training. No significant change was found in LoHi group. Compared with that before hypoxic exposure, no significant change in∑T/R was found in both groups. 2. Diastolic thickness of left interventricular Septum (IVSd), Systolic thickness of posterior wall of left ventricle (LVPWs), Muscle mass of left ventricle (LV MASS), Muscle mass of left ventricle in relation to body mass (LVMI) and blood pressure measured in silence after hypoxic training in HiHiLo group were greater as compared with that before hypoxic training (p<0.05). Enddiastolic diameter of right ventricle (RVD) in HiHiLo group was smaller as compared with that before hypoxic training (p<0.05), Diastolic filling time of mitral valve (DFT) was extended in silence and under load in HiHiLo group as compared with that before hypoxic training (p<0.05). 3. Diastolic thickness of left interventricular Septum (IVSd) and Systolic thickness of posterior wall of left ventricle (LVPWs) of LoHi group in silence after hypoxic training were greater as compared with that before hypoxic training (p<0.05), Endsystolic diameter of left ventricle (LVDs) in LoHi group was smaller in silence and under load as compared with that before hypoxic training (p<0.05), Endsystolic volume of left ventricle (ESV) in LoHi group was smaller under load as compared with that before hypoxic training (p<0.05), shortening fraction (FS) and ejection fraction (EF) in LoHi group increased as compared with that before hypoxic training (p<0.05). 4. Muscle mass of left ventricle in relation to body mass (LVMI) and Systolic blood pressure in HiHiLo group after hypoxic training were greater as compared with that in LoHi group (p<0.05). there was some difference with Diastolic filling time of mitral valve (DFT) under load after hypoxic training in both groups.Conclusion: The hypoxic training had no negative effect on cardiac function. Whereas living in hypoxic condition facilitated the recovery of cardiac function after training. There was an improvement in cardiac function in HiHiLo group and LoHi group after hypoxic training, the heart gained good adaptability.