Relationship between ventilation and predicted arterial CO2 pressure during recovery from an impulse-like exercise without metabolic acidosis Authors

We investigated ventilation (V ． E) control factors during recovery from light impulse-like exercise (100 watts) with a duration of 20 sec. Blood ions and gases were measured at rest and during recovery. V ． E, end tidal CO 2 pressure (PETCO 2) and respiratory exchange ratio (RER) were measured continuously during rest, exercise and recovery periods. Arterial CO2 pressure (PaCO 2 pre) was estimated from PETCO 2 and tidal volume (V T). RER at 20 sec of exercise and until 50 sec during recovery was significantly lower than RER at rest. Despite no change in arterialized blood pH level, PaCO 2 pre was significantly higher in the last 10 sec of exercise and until 70 sec during recovery than the resting value. V ． E increased during exercise and then decreased during recovery; however, it was elevated and was significantly higher than the resting value until 155 sec (p<0.05). There was a significant relationship between V ． E and PaCO 2 pre during the first 70 sec of recovery in each subject. The results suggest that PaCO 2 drives V ． E during the first 70 sec of recovery after light impulse-like exercise. Elevated V ． E in the interval from 70 sec until 155 sec during recovery might be due to neural factors.