Postexercise Cooling Rates in 2 Cooling Jackets

Context: Cooling jackets are a common method for removing stored heat accumulated during exercise. To date, the efficiency and practicality of different types of cooling jackets have received minimal investigation. Objective: To examine whether a cooling jacket containing a phase-change material (PC17) results in more rapid postexercise cooling than a gel cooling jacket and a no-jacket (control) condition. Design: Randomized, counterbalanced design with 3 experimental conditions. Setting: Participants exercised at 75% (V) over doto(2) max workload in a hot climate chamber (temperature = 35.0 +/- 1.4 degrees C, relative humidity = 52 +/- 4%) for 30 minutes, followed by postexercise cooling for 30 minutes in cool laboratory conditions (ambient temperature = 24.9 +/- 1.8 degrees C, relative humidity = 39% +/- 10%). Patients or Other Participants: Twelve physically active men (age = 21.3 +/- 1.1 years, height = 182.7 +/- 7.1 cm, body mass = 76.2 +/- 9.5 kg, sum of 6 skinfolds = 50.5 +/- 6.9 mm, body surface area = 1.98 +/- 0.14 m(2), (V) over dotO(2) max = 49.0 +/- 7.0 mL.kg(-1).min(-1)) participated. Intervention(s): Three experimental conditions, consisting of a PC17 jacket, a gel jacket, and no jacket. Main Outcome Measure(s): Core temperature (T-C), mean skin temperature (T-Sk), and T-C cooling rate (degrees C/min). Results: Mean peak T-C postexercise was 38.49 +/- 0.42 degrees C, 38.57 +/- 0.41 degrees C, and 38.55 +/- 0.40 degrees C for the PC 17 jacket, gel jacket, and control conditions, respectively. No differences were observed in peak Tc cooling rates among the PC17 jacket (0.038 +/- 0.007 degrees C/min), gel jacket (0.040 +/- 0.009 degrees C/min), and control (0.034 +/- 0.010 degrees C/min, P > .05) conditions. Between trials, no differences were calculated for mean T-Sk cooling. Conclusions: Similar cooling rates for all 3 conditions indicate that there is no benefit associated with wearing the PC17 or gel jacket.