Bishop, SH, Szymanski, DJ, Ryan, GA, Herron, RL, and Bishop, PA. The effect of intermittent vest cooling on thermoregulation and cardiovascular strain in baseball catchers. J Strength Cond Res 31(8): 2060–2065, 2017—Baseball catchers are exposed to multiple physiological challenges while playing outside during the spring and summer months, many of which deal with recovery and thermoregulation. The purpose of this study was to investigate the effect of intermittent cooling on core temperature, cardiovascular strain, exertion, and recovery during a simulated catching performance in the heat. Six trained college-aged baseball catchers performed in a controlled, hot (35° C), and humid (25% relative humidity) environment in a counter-balanced, cross-over design. Ice vest cooling (VC) was used as a cooling modality and was compared with a control of no cooling (NC). Rectal temperature (Tre), heart rate (HR), rating of perceived exertion (RPE), and perceived recovery scale (PRS) were recorded before and after each simulated inning. All activities took place in a heat chamber, and each inning consisted of catchers receiving 12 pitches in their position followed by 6 minutes of recovery. Nine total innings were performed, and 27 total innings were performed with each of the 2 treatments. A significantly smaller mean Tre change was seen in VC when compared with NC (0.58 ± 0.2° C, 0.98 ± 0.2° C, p ≤ 0.01, respectively). Rating of perceived exertion was significantly lower and PRS was significantly improved for VC compared with NC (both p ≤ 0.05). Mean recovery HR during VC was significantly lower than NC in the fifth (VC = 84 ± 8 b·min−1, NC = 90 ± 9 b·min−1, p = 0.04), seventh (VC = 84 ± 3 b·min−1, NC = 92 ± 7 b·min−1, p = 0.02), and ninth (VC = 85 ± 7 b·min−1, NC = 93 ± 5 b·min−1, p = 0.01) innings. Heart rate during catching was significantly lower at the end of the VC trials when compared with NC (108 ± 16 b·min−1 vs. 120 ± 19 b·min−1, p = 0.02, respectively). Vest cooling decreased heat strain, cardiovascular strain, and RPE while it improved perceived recovery in catchers over a simulated 3-game series performed in hot conditions.