ORIGINAL ARTICLES   

The Journal of Sports Medicine and Physical Fitness 1998 March;38(1):24-9

Copyright © 1998 EDIZIONI MINERVA MEDICA

language: English

Changes in plasma volume following intense intermittent exercise in neutral and hot environmental conditions

Rotstein A. ¹, Falk B. ², Einbinder M. ², Zigel L. ²

¹ Zinman College of Physical Education and Sport Sciences, Wingate Institute, Netanya, Israel; ² Ribstein Center for Research and Sport Medicine Sciences, Wingate Institute, Netanya, Israel

Back­ground. The pur­pose of the ­present inves­ti­ga­tion was to ­examine the ­effect of supra­max­imal ­short dura­tion inter­mit­tent exer­cise in neu­tral and hot envi­ron­mental con­di­tions on ­changes in ­plasma ­volume. The ­return of ­plasma ­volume (PV) to pre-exer­cise ­values fol­lowing dif­ferent ­recovery con­di­tions was ­also exam­ined.
­Methods. Experi­mental ­design. ­Within sub­ject ­design in ­which one way anal­ysis of var­i­ance was con­ducted.
Set­ting. ­Research, ­sports sci­ence aca­demic insti­tute.
Par­tic­i­pants. Ten ­trained men, 25.5±3/1 (yrs), vol­un­teers.
Inter­ven­tions. Sub­jects per­formed six 1-min ­bouts of exer­cise at 100% V.O2­peak on a ­cycle ergom­eter, ­with 4-min ­rest inter­vals ­between the ­bouts. ­Each sub­ject exer­cised ­twice in ther­mo­neu­tral (22°C, 40% RH) and ­twice in hot (35°C, 30% RH) con­di­tions. Exer­cise was fol­lowed by ­either 40 min of pas­sive ­recovery (sit­ting) or by 20 min ­active ­recovery (­cycling at 35% V.O2­peak) and 20 min pas­sive ­recovery, ­named there­after “active ­recovery”.
Meas­ures. Hema­tocrit (Hct) and hemo­globin (Hb) ­were deter­mined ­upon ­entry ­into the cli­matic ­chamber fol­lowing 20 min ­rest in the ­chamber (pre-exer­cise), imme­di­ately ­postexer­cise, and 40 min ­postexer­cise. ­From the ­changes in Hct and Hb, PV ­changes ­were cal­cu­lated.
­Results. ­There was a sig­nif­i­cant ­decrease in PV imme­di­ately ­postexer­cise. How­ever, ­there was no sig­nif­i­cant dif­fer­ence ­between the two ­types of envi­ron­mental con­di­tions and no dif­fer­ence ­between the two ­types of ­recovery. PV ­increased sig­nif­i­cantly fol­lowing ­recovery and ­returned to pre-exer­cise ­values fol­lowing 40 min of ­recovery.
Con­clu­sions. ­Changes in PV ­caused by max­imal ­short dura­tion ­cycling ­bouts is not ­affected by envi­ron­mental con­di­tions, PV ­returns to its pre-exer­cise ­values ­within 40 min of ­recovery regard­less of the ­recovery ­mode.