This study examined the relation between excessive CO2 expiration and exercise performance in exercise exhausted for 1-2 min. First, the Wingate test was conducted to determine the exercise intensity of the performance test. The exercise intensity was set at 80% of the power exerted during the last 5 s of the Wingate test so that subjects could continue for 1-2 min. Total work, which was the value of the work rate times the performed duration was used as an index of the performance level. The excessive CO2 expiration rate (‡CO2excess) was defined as the difference between CO2 output and O2 uptake. Integration of ‡CO2excess from the start of exercise to the zero level of ‡CO2excess observed at around 10 min in recovery was defined as the amount of excessive CO2 expiration (CO2excess). The performance was associated with the peak value of blood lactate (peak La) obtained after exercise (r=0.744). The performance was also associated with CO2excess (r=0.848). It is likely that CO2excess is a better physiological index for assessing the performance in exercise exhausted for 1-2 min than peak La
