Changes in Cardiac Tone Regulation with Fatigue after Supra-Maximal Running Exercise. (30th April 2012)

• Record Type: Journal Article
• Authors: Leprêtre, Pierre-Marie; Lopes, Philippe; Thomas, Claire; Hanon, Christine
• Other Names: Balbi Bruno Academic Editor.
• Is Part Of: TheScientificWorldjournal. Volume 2012(2012)
• Publication Date: 2012-04-30
• Subjects: Science -- Periodicals; Technology -- Periodicals; Medicine -- Periodicals; 505
• DOI: 10.1100/2012/281265
• Languages: English
• ISSNs: 2356-6140

Abstract

Abstract : To investigate the effects of fatigue and metabolite accumulation on the postexercicse parasympathetic reactivation, 11 long-sprint runners performed on an outdoor track an exhaustive 400 m long sprint event and a 300 m with the same 400 m pacing strategy. Time constant of heart rate recovery (HRRτ ), time (RMSSD), and frequency (HF, and LF) varying vagal-related heart rate variability indexes were assessed during the 7 min period immediately following exercise. Biochemical parameters (blood lactate, pH, PO2, PCO2, SaO2, and HCO3 − ) were measured at 1, 4 and 7 min after exercise. Time to perform 300 m was not significantly different between both running trials. HHRτ measured after the 400 m running exercise was longer compared to 300 m running bouts (183.7 ± 11.6 versus 132.1 ± 9.8 s, P < 0.01 ). Absolute power density in the LF and HF bands was also lower after 400 m compared to the 300 m trial (P < 0.05 ). No correlation was found between biochemical and cardiac recovery responses except for the PO2 values which were significantly correlated with HF levels measured 4 min after both bouts. Thus, it appears that fatigue rather than metabolic stresses occurring during a supramaximal exercise could explain the delayed postexercise parasympathetic reactivation in longer sprint runs.