PURPOSE: The present study investigated whether advanced footwear technology alters thermoregulatory and metabolic responses during running in a hot environment. METHODS: In a randomized crossover design, 14 trained male runners (V̇O2peak: 55.0 ± 3.7 mL·kg⁻¹·min⁻¹) performed treadmill running while wearing traditional running shoes (Hyper Speed 3; CON) or advanced footwear (Metaspeed Sky Paris; SKY) in a hot environment (30°C, 40% RH). On each experimental trial, participants firstly completed two 5-min running economy tests at 12 km·h⁻¹: the first in CON (RE1) and the second in the assigned shoes (CON or SKY; RE2). While continuing to wear the RE2 shoes, participants then performed two 30-min runs at 60% and 80% V̇O2peak, during which metabolic and thermoregulatory variables were continuously measured. RESULTS: V̇O₂ was reduced in SKY compared with CON by 3.4 ± 3.1% during the 5-min test and by 2.5 ± 4.2% on average during the prolonged trials (both P≤0.031). However, metabolic heat production (M) and rectal temperature did not differ between shoe conditions during the prolonged exercise (both P≥0.070). In contrast, when wearing SKY, the evaporative requirement for heat balance (Ereq; Δ5.4 ± 5.3%, P=0.013) and whole-body sweat loss (Δ54 ± 71 g, P=0.018) were reduced compared with CON. These changes were accompanied by an elevated mean skin temperature (Δ0.31 ± 0.48°C, P=0.045) and increased dry heat loss via radiation and convection (Δ12.2 ± 17.5%, P=0.015) in SKY. CONCLUSIONS: Advanced footwear technology reduces metabolic cost and attenuates Ereq and sweat production while increasing skin temperature and reliance on dry heat dissipation during running in hot conditions. The magnitude of metabolic savings was likely insufficient to influence M or core body temperature.
Otsuka et al. (Fri,) studied this question.