Exercise-induced plasma volume expansion and post-exercise parasympathetic reactivation

• Published in: European journal of applied physiology Vol. 105; no. 3; pp. 471 - 481
• Main Authors: Buchheit, M., Laursen, P. B., Al Haddad, H., Ahmaidi, S.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.02.2009; Springer Nature B.V
• Subjects: Biomedical and Life Sciences; Biomedicine; Blood; Erythrocyte Indices - physiology; Exercise; Exercise - physiology; Exercise Test; Exercise Tolerance; Heart rate; Heart Rate - physiology; Hematocrit; Homeostasis - physiology; Human Physiology; Humans; Male; Occupational Medicine/Industrial Medicine; Original Article; Parasympathetic Nervous System - physiology; Physical fitness; Plasma; Plasma Volume - physiology; Running - physiology; Sports Medicine; Young Adult; Supramaximal training; Heart rate recovery; Heart rate variability; Plasma volume expansion
• ISSN: 1439-6319; 1439-6327
• DOI: 10.1007/s00421-008-0925-1

The purpose of this study was to investigate the effect of exercise-induced plasma volume expansion on post-exercise parasympathetic reactivation. Before (D 0 ) and 2 days after (D +2 ) a supramaximal exercise session, 11 men (21.4 ± 2.6 years and BMI = 23.0 ± 1.4) performed 6-min of submaximal running where heart rate (HR) recovery (HRR) and HR variability (HRV) indices were calculated during the first 10 min of recovery. Relative plasma volume changes (∆PV) were calculated using changes in hematocrit and hemoglobin measured over consecutive mornings from D 0 to D +2 . Parasympathetic reactivation was evaluated through HRR and vagal-related indexes calculated during a stationary period of recovery. Compared with D 0 , ∆PV (+4.8%, P  < 0.01) and all vagal-related HRV indices were significantly higher at D +2 (all P  < 0.05). HRR was not different between trials. Changes in HRV indices, but not HRR, were related to ∆PV (all P  < 0.01). HRR and HRV indices characterize distinct independent aspects of cardiac parasympathetic function, with HRV indices being more sensitive to changes in plasma volume than HRR.