title: Parasympathetic reactivation after maximal CPET depends on exercise modality and resting vagal activity in healthy men.
abstract: OBJECTIVE
  The main purpose of this study was to investigate parasympathetic reactivation of the heart [evaluated through heart rate recovery (HRR) and HR variability (HRV)] after maximal cardiopulmonary exercise testing (CPET) using three different exercise modalities.
  
  
  METHODS
  Twenty healthy men, aged 17 to 28 yr, performed three maximal CPETs (cycling, walking, and running) separated by 72 h and in a randomized, counter-balanced order. HRR was determined from the absolute differences between HRpeak and HR at 1-3 min after exercise. The root mean square of successive R-R differences calculated for consecutive 30-s windows (rMSSD30s) was calculated to assess the parasympathetic reactivation after maximal CPET.
  
  
  RESULTS
  Lower HRpeak, VO2peak and energy expenditure were observed after the cycling CPET than the walking and running CPETs (P < 0.001). Both HRR and rMSSD30s were significantly greater during recovery from the cycling CPET compared to the walking and running CPETs (P < 0.001). Furthermore, Δ rMSSD (i.e. resting minus postexercise rMSSD every 30 s into the recovery period) was positively related to the resting high-frequency component (HF), rMSSD, and standard deviation of all normal R-R intervals (SDNN) (rs = 0.89 to 0.98; P < 0.001), and negatively related to the resting low-frequency component (LF) and sympathovagal balance (LF:HF ratio) after all exercise conditions (rs = -0.73 to -0.79 and -0.86 to -0.90, respectively; P < 0.001).
  
  
  CONCLUSIONS
  These findings support that parasympathetic reactivation after maximal CPET (as assessed by HRR and rMSSD30s) depends on exercise modality and cardiac autonomic control at rest.
authors: Medical Sciences Graduate Program, Faculty of Medical Sciences, University of Rio de Janeiro State, Rio de Janeiro, Brazil ; Institute of Physical Education and Sports, Laboratory of Physical Activity and Health Promotion, University of Rio de Janeiro State, Rio de Janeiro, Brazil.
authors: Felipe A
authors: FA
authors: Cunha
authors: Department of Sport and Physical Activity, Edge Hill University, Ormskirk, Lancashire, UK.
authors: Adrian W
authors: AW
authors: Midgley
authors: Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil.
authors: Thiago
authors: T
authors: Gonçalves
authors: Department of Physiology and Pharmacology, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil.
authors: Pedro P
authors: PP
authors: Soares
authors: Institute of Physical Education and Sports, Laboratory of Physical Activity and Health Promotion, University of Rio de Janeiro State, Rio de Janeiro, Brazil ; Physical Activity Sciences Graduate Program, Salgado de Oliveira University, Niterói, Brazil.
authors: Paulo
authors: P
authors: Farinatti
keywords: Autonomic nervous system; Cardiopulmonary exercise testing; Ergometry; Heart rate recovery; Heart rate variability; Spectral analysis