ABSTRACT
Introduction:
The evaluation of cardiac autonomic function (CAF) after stress test (ST) is considered a powerful and independent predictor of cardiovascular risk. The knowledge about the influence of different recovery protocols on CAF after ST on treadmill with volunteers in standing position is scarce.
Objective:
To compare the vagal reactivation and the degree of global CAF modulation in two different recovery protocols, passive (PR) vs. active (AR) immediately after submaximal ST in treadmill.
Methods:
We evaluated 24 physically active males, aged (mean ± SD) 27.2 ± 4.4 years and BMI 24.8 ± 1.8 kg/m2. The order of the recovery protocol was set at random. The tests were performed in 7-day intervals. Both recovery protocols were performed in standing position for 5 minutes, immediately after ST. The time indices of heart rate variability were used to assess the vagal reactivation and the overall degree of CAF, rMSSD, and SDNN, respectively, in PR and AR. After analysis of the data distribution, the Mann-Whitney and Friedman tests with Dum post-hoc were used at a significance level of p ≤ 0.05.
Results:
We observed a higher vagal reactivation at first minute of the PR compared to AR [4.1 (4.9-3.4) ms vs. 3.4 (4.0-2.9) ms, p = 0.03], and a higher degree of global CAF modulation from the third to the fifth minute and a tendency to significant difference in the second minute of PR compared to AR (p = 0.09−0.005).
Conclusion:
The findings demonstrate that minimum physical effort, such as walking slowly on a treadmill, decreased the vagal reactivation and the overall modulation degree of CAF after a submaximal ST in physically active men.
Keywords:
parasympathetic nervous system; heart rate; exercise; physical exertion.
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