In a thin full-body race suit with a 5 m/s wind, hard running was best at −4 to +1 °C and already impaired at +10 °C
The best temperature depends on what is worn
Key Findings
Time to exhaustion was longer at −4 and 1 °C than at −14, 10 and 20 °C; running speed at the lactate threshold was higher at −4 °C than at −9, 10 and 20 °C.
Nine male endurance athletes in a cross-country ski racing suit ran a standard test at six temperatures with a wind speed of 5 m/s.
The authors conclude that optimal performance in that suit was at −4 and 1 °C, and that performance was reduced in moderately warm (10 and 20 °C) and cold (−14 and −9 °C) conditions.
Practical Application
At race effort even a thin full-length layer is too much at +10 °C. For a 10 km or a hard tempo at 10–12 °C, race in summer kit (shorts and a short-sleeved or sleeveless top); add gloves or arm warmers if the hands and forearms get cold — the garments are practice, the direction is the finding.
The warm clothes belong before the start, not during the race.
Limitations
N = 9 trained men, short treadmill protocol, one garment. Abstract only was read.