Compression garments do not enhance high intensity exercise in hot radiant conditions

Purpose: To establish the thermal and performance effects of wearing a lower-body graduated compression garment (GCG; COMPRESSION) in a hot environment (35.2 (0.1)°C) with a representative radiant heat load (~800 W.m2) in contrast to a CONTROL (running shorts) and SHAM condition (a compression garment 1-size larger than that recommended by the manufacturer) with the latter included to establish any placebo effect. Method: Eight participants (mean [SD]); age 21 [2]years; height 1.77 [0.06]m; mass 72.8 [7.1]kg; surface area, 1.89 [0.10]m2) completed three treadmill tests at a fixed speed for 15-minutes followed by a self-paced 5 kilometre time trial (TT). Performance (completion time) and pacing (split time), thermal responses (aural [Tau], skin [Tskin], mean body temperature [Tb], cardiac frequency [fc]) and perceptual responses (rating of perceived exertion [RPE], thermal sensation [TS], thermal comfort [TC]) were measured. Results: Performance in COMPRESSION was not different to either SHAM or CONTROL at any stage (p>0.05); completion time 26.08 (4.08), 26.05 (3.27), 25.18 (3.15) minutes, respectively. At the end of the 5 km TT, RPE was not different; 19 (1) across conditions. In general, thermal and perceptual responses were not different although the radiant heat load increased site-specific skin temperature (quadricep) in the garment conditions. Conclusion: GCG did not enhance performance in a hot environment with a representative radiant heat load. The SHAM treatment did not benefit perception. GCG provided no evidence of performance enhancement.