The effects of carbonated cold water immersion of the arm during half-time on intermittent exercise performance in...

To investigate the effect of half-time cooling via single arm immersion in carbonated water (CO₂WI) during intermittent exercise in the heat (34.63 ± 0.49 °C, 54.2 ± 1.8% relative humidity [RH]).

Eight male and two female recreational athletes (age: 26 ± 3; height: 176.5 ± 6.2 cm; body mass: 73.3 ± 11.4 kg) completed 2 × 39 min sprint cycling, interspersed by a 13-min single arm cooling (21.79 ± 0.76 °C, 64.5 ± 2.4%RH): (1) cold water immersion (CWI, 9.56 ± 0.60 °C); (2) cold CO₂ water (CO₂WI, 9.37 ± 0.51 °C); and (3) control condition (CON). Rectal (T_re) and skin temperature (T_sk), heart rate (HR), working memory (serial 7), mean (MPO), peak power output (PPO), thermal sensation, thermal comfort, rating of perceived exertion (RPE) and whole-body sweat loss (WBS) were assessed.

During cooling, reduction in T_re was 0.15 °C greater in CWI versus CON only (p = 0.031), and reductions in T_sk were 1.18 °C and 0.38 °C greater in CO₂WI versus CON (p = 0.007) and CWI (p = 0.038). When normalised to the first half, percentage decrease in MPO was greater in CON versus CWI by 4.2% (p = 0.055), whereas percentage change in PPO was similar between conditions (p = 0.280). WBS, thermal comfort, thermal sensation, HR, working memory and RPE were similar between conditions (p > 0.05).

CO₂WI did not have additional ergogenic effects than CWI. Furthermore, both CWI and CO₂WI did not decrease T_re or improve thermal perception appreciably more than CON.