Effects of Performance Enhancing Clothing on Cardiovascular Endurance

Abstract

Performance enhancing garments have attempted to improve cardiovascular endurance by increasing venous return via compression technology or to improve thermoregulation to increase endurance by decreasing thermal stress. Recently developed proprietary clothing technology claims to increase cardiovascular endurance by altering the electromagnetic microclimate next to the skin, possibly increasing vasodilation. PURPOSE: To compare cardiovascular endurance using the Chester Step Test in novel technology clothing using a randomized double blind trial with deception. METHODS: 15 healthy adult athletes (9 females, 6 males 29 +/-5 yrs; low to high intensity exerciser 2-6 x week) gave informed consent to participate in this IRB-approved protocol. The athletes completed 4 exercise sessions over 9 days, performing the Chester Step Test with Polar heart rate monitor to record participants’ heart rates on a iPad. The athlete stepped onto and off a 30.5 cm box at 60 Hz using a metronome. Every two minutes heart rate and Rating of Perceived Exertion (RPE) using the Borg scale were checked and stepping rate was increased by 20 Hz. The test was stopped once the athlete reached 80% heart rate maximum, the athlete was unable to keep the set pace, or intensity was moderately hard (>=14) using RPE. The athletes wore t-shirts and shorts that were identical in look and feel except for the technology treatment (enhanced) or not (control). Conditions were tested in random order: True Positive (athlete told they were in the enhanced clothing and were in the enhanced clothing; True Negative (athlete told they were in control clothing and were in control clothing; False Positive (athlete told they were enhanced clothing but were not); and False Negative (athlete told they were not in enhanced clothing but were). The endurance times were compared using a repeated measures ANOVA. RESULTS: There was no statistically significant difference in the endurance test duration in any of the conditions (main effect P = 0.53). True Positive 361.3 ± 106.4 sec; True Negative 362.2 ± 94.2 sec; False Positive 365.5 ± 85.5; and False Negative 332.1 ± 107.0 sec. CONCLUSION: It appears from these data that the enhanced technology clothing did not improve endurance exercise duration, nor did the awareness of the enhanced clothing improve endurance exercise duration.