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 o(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 o(2)max = 49.0 +/- 7.0 mLxkg(-1)xmin(-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 PC17 jacket, gel jacket, and control conditions, respectively. No differences were observed in peak T(C) 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.