Can a short-term hiking training change cardiovascular autonomic control in healthy sedentary women?

We tested the hypothesis that two weeks of training performed at moderate intensity can induce cardiovascular autonomic control changes in adult sedentary women. To this aim, we continuously recorded finger arterial pressure in 8 women (25 yy ± 7; 68 kg ± 11, 165 cm ± 8) before and immediately after a training program of daily trekking (3-6 hours d-1) performed at near sea level and on irregular and undulating terrain. 8 min records were taken in 3 steady state conditions: 1) supine, 2) 70° passive head up tilting, 3) back to supine. Pressure waveforms were transformed into time series of systolic and diastolic pressure, heart rate, stroke volume, cardiac output and total peripheral resistance. Pressure and heart rate time series underwent auto and cross correlation spectral analysis to detect spontaneous oscillations in the low (0.05-0.15 Hz) and high (0.20-0.30 Hz) frequency range. All variables (measured and calculated) were compared in the three conditions before and after training; also transients (tilt-up/tilt-down) were recorded and visually compared. Overall, we did not find pre/post training significant differences in any of the variables, both in the time and in the frequency domain. Also the time course of changes during tilt-up and down was quite similar for individual subjects. We concluded that two weeks of training performed at moderate intensity were not able to induce significant changes in the cardiovascular autonomic control.