Effect Of Circuit Weight Training On Autonomic Nerve System Function Of Young Healthy Subjects

Purpose:Autonomic function can be improved by long term aerobic exercise training, while traditional resistance training has a limited impact. However, much less is known of the effects of circuit weight training on autonomic cardiovascular regulation. The present research observed the effects of 12 weeks circuit weight training on autonomic cardiovascular regulation of young healthy subjects. Results from this project may provide support for choosing the appropriate exercise prescription for different individuals.Methods:24 young (18 to 30 years) healthy subjects were assigned to exercise (EG, n=13) and control (CG, n=11) groups. Subjects in the EG group underwent a circuit weight training program that consisted of 7 exercises performed in 3 sets of 15 repetitions with 15-30 seconds rest 3 days per week for 12 weeks. Whole-body muscular strength, resting metabolic rate, body composition and aerobic capacity were measured before and after training. Blood pressure, pulse wave velocity and autonomic function were tested every four weeks throughout the 12 week program. Autonomic function tests consisted of subjects preforming 5 minutes controlled frequency breathing (0.25 Hz), and three Valsalva’s maneuvers while we recording synchronous ECG, beat-by-beat blood pressure and muscle sympathetic nerve signals. MSNA was recorded directly using microneurography. HRV was estimated through time and frequency domain analysis of R-R intervals during controlled frequency breathing. Spontaneous cardiovagal BRS was estimated through sequence method, dynamic cardiovagal baroreflex sensitivity was derived from increases of R-R intervals as functions of increases in systolic pressures with linear regression analysis during phaseⅣpressure increases, and sympathetic sensitivity was derived from the quotient of total muscle sympathetic nerve activity and diastolic pressure changes during phaseⅡpressure reductions.Results:(1) Circuit weight training increased whole-body muscular strength (289±30.8 pre-, and 396.4±35.5 Kg posttraining; mean±SE; p<0.01) and V02 max (2.46±0.3 pre-, and 2.91±0.2 L/min posttraining; mean±SE; p<0.05). RMR and body fat percentage were not changed.(2) Peripheral and central pulse wave velocities were not changed throughout 12 weeks training as well as arterial systolic and diastolic blood pressure.(3) Circuit weight training didn’t change HRV or cardiovagal baroreflex sensitivity.Conclusion:Circuit weight training increases muscle strength and aerobic capacity, but does not affect blood pressure, arterial compliance and autonomic nerve function in young healthy subjects.