%0 Journal Article
%T Effect of water immersion temperature on heart rate variability following exercise in the heat
%A C. Choo
%A Hui
%A C. Yeo
%A Chow
%A Ihsan
%A Mohammed
%A J. Peiffer
%A Jeremiah
%A Nosaka
%A Kazunori
%A R. Abbiss
%A Chris
%J -
%D 2018
%X Sa£¿etak This study compared the effect of passive rest (CON) and water immersion at 8.6¡À0.2¡ãC (CWI9), 14.6¡À0.3¡ãC (CWI15) and 35.0¡À0.4¡ãC (thermoneutral water immersion [TWI]) on post-exercise heart rate variability (HRV) indices. In a climate chamber (32.8¡À0.4¡ãC, 32¡À5% relative humidity), nine men completed 25 min of cycling at the first ventilatory threshold and repeated 30-second bouts at 90% of peak power followed by a 5-minute recovery treatment in a randomised crossover manner. All water immersion re-established the HRV indices (natural logarithm of the square root of the mean sum squared differences between RR intervals [ln rMSSD], low-frequency [lnLF] and high-frequency power densities [lnHF] and Poincar¨¦ plotderived measures [lnSD1 and lnSD2]) to the pre-exercise levels at 60 min post immersion; however, only CWI9 accelerated parasympathetic reactivation during immersion. CWI9 increased lnLF and lnSD2 during immersion when compared with CON (p<.05). Although CWI9 had a large positive effect size (ES>0.80) on all HRV indices during immersion when compared with CON, between-conditions differences were observed only in lnLF and lnSD2 (p=.017-.023). CWI15 had a large positive ES on ln rMSSD and lnSD1 when compared with CON (both p=.064). Sympathovagal antagonism (i.e., SD ratio<0.15) did not occur during CWI9 and CWI15. Hence, both CWI treatments are effective means of enhancing post-exercise parasympathetic reactivation, but CWI9 is likely to be more effective at increasing post-exercise cardiac vagal tone
%K autonomic cardiovascular control
%K cooling
%K recovery
%K hydrotherapy
%K vagal modulation
%U https://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=284204