AUTHOR=Seeley Afton D. , Sherman Ross A. 

TITLE=An Ice Vest, but Not Single-Hand Cooling, Is Effective at Reducing Thermo-Physiological Strain During Exercise Recovery in the Heat

JOURNAL=Frontiers in Sports and Active Living

VOLUME=3

YEAR=2021

URL=https://www.frontiersin.org/journals/sports-and-active-living/articles/10.3389/fspor.2021.660910

DOI=10.3389/fspor.2021.660910

ISSN=2624-9367

ABSTRACT=<p>Sports limit the length of breaks between halves or periods, placing substantial time constraints on cooling effectiveness. This study investigated the effect of active cooling during both time-limited and prolonged post-exercise recovery in the heat. Ten recreationally-active adults (VO<sub>2peak</sub> 43.6 ± 7.5 ml·kg<sup>−1</sup>·min<sup>−1</sup>) were exposed to thermally-challenging conditions (36°C air temperature, 45% RH) while passively seated for 30 min, cycling for 60 min at 51% VO<sub>2peak</sub>, and during a seated recovery for 60 min that was broken into two epochs: first 15 min (REC<sub>0−15</sub>) and total 60 min (REC<sub>0−60</sub>). Three different cooling techniques were implemented during independent recovery trials: (a) negative-pressure single hand-cooling (~17°C); (b) ice vest; and (c) non-cooling control. Change in rectal temperature (<italic>T</italic><sub>re</sub>), mean skin temperature (<inline-formula><mml:math id="M1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mover accent="false" class="mml-overline"><mml:mrow><mml:mi>T</mml:mi></mml:mrow><mml:mo accent="true">¯</mml:mo></mml:mover></mml:mrow><mml:mrow><mml:mtext>sk</mml:mtext></mml:mrow></mml:msub></mml:math></inline-formula>), heart rate (HR), and thermal sensation (TS), as well as mean body temperature (<inline-formula><mml:math id="M2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mover accent="false" class="mml-overline"><mml:mrow><mml:mi>T</mml:mi></mml:mrow><mml:mo accent="true">¯</mml:mo></mml:mover></mml:mrow><mml:mrow><mml:mtext>b</mml:mtext></mml:mrow></mml:msub></mml:math></inline-formula>), and heat storage (<italic>S</italic>) were calculated for exercise, REC<sub>0−15</sub> and REC<sub>0−60</sub>. During REC<sub>0−15</sub>, HR was lowered more with the ice vest (−9 [−15 to −3] bts·min<sup>−1</sup>, <italic>p</italic> = 0.002) and single hand-cooling (−7 [−13 to −1] bts·min<sup>−1</sup>, <italic>p</italic> = 0.021) compared to a non-cooling control. The ice vest caused a greater change in <inline-formula><mml:math id="M3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mover accent="false" class="mml-overline"><mml:mrow><mml:mi>T</mml:mi></mml:mrow><mml:mo accent="true">¯</mml:mo></mml:mover></mml:mrow><mml:mrow><mml:mtext>sk</mml:mtext></mml:mrow></mml:msub></mml:math></inline-formula> compared to no cooling (−1.07 [−2.00 to −0.13]°C, <italic>p</italic> = 0.021) and single-hand cooling (−1.07 [−2.01 to −0.14]°C, <italic>p</italic> = 0.020), as well as a greater change in <italic>S</italic> compared to no cooling (−84 [−132 to −37] W, <italic>p</italic> &lt; 0.0001) and single-hand cooling (−74 [−125 to −24] W, <italic>p</italic> = 0.002). Across REC<sub>0−60</sub>, changes in <inline-formula><mml:math id="M4" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mover accent="false" class="mml-overline"><mml:mrow><mml:mi>T</mml:mi></mml:mrow><mml:mo accent="true">¯</mml:mo></mml:mover></mml:mrow><mml:mrow><mml:mtext>b</mml:mtext></mml:mrow></mml:msub></mml:math></inline-formula> (−0.38 [−0.69 to −0.07]°C, <italic>p</italic> = 0.012) and <inline-formula><mml:math id="M5" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mover accent="false" class="mml-overline"><mml:mrow><mml:mi>T</mml:mi></mml:mrow><mml:mo accent="true">¯</mml:mo></mml:mover></mml:mrow><mml:mrow><mml:mtext>sk</mml:mtext></mml:mrow></mml:msub></mml:math></inline-formula> (−1.62 [−2.56 to −0.68]°C, <italic>p</italic> &lt; 0.0001) were greater with ice vest compared to no cooling. Furthermore, changes in in <inline-formula><mml:math id="M6" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mover accent="false" class="mml-overline"><mml:mrow><mml:mi>T</mml:mi></mml:mrow><mml:mo accent="true">¯</mml:mo></mml:mover></mml:mrow><mml:mrow><mml:mtext>b</mml:mtext></mml:mrow></mml:msub></mml:math></inline-formula> (−0.39 [−0.70 to −0.08]°C, <italic>p</italic> = 0.010) and <inline-formula><mml:math id="M7" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mover accent="false" class="mml-overline"><mml:mrow><mml:mi>T</mml:mi></mml:mrow><mml:mo accent="true">¯</mml:mo></mml:mover></mml:mrow><mml:mrow><mml:mtext>sk</mml:mtext></mml:mrow></mml:msub></mml:math></inline-formula> (−1.68 [−2.61 to −0.74]°C, <italic>p</italic> &lt; 0.0001) were greater with the ice vest compared to single-hand cooling. Using an ice vest during time-limited and prolonged recovery in the heat aided in a more effective reduction in thermo-physiological strain compared to both passive cooling as well as a single-hand cooling device.</p>