Abstract. We examined the effects of fluid and food intake on cardiopulmonary status during cardiopulmonary exercise testing (CPX). Twelve young men fasted for 12 hours, followed by CPX under three experimental conditions: 1) continuation of fasting; 2) ingestion of 420 ml of water; and 3) ingestion of 420 g of jelly. For the second and third experimental conditions a 30-min time lapse was imposed after intake of water or food before CPX. Each participant then underwent symptom-limited maximal CPX and also acted as his own control for each experimental condition. The respiratory gas exchange ratio was significantly smaller in the water condition (0.76 ± 0.06) than in the fasting (0.83 ± 0.01) and jelly (0.83 ± 0.05) conditions at rest, but no other differences in cardiopulmonary responses were evident. These findings suggest that blood distribution to skeletal muscles is prioritized at maximal exercise level even during the digestion and absorption of food. In conclusion, careful consideration should be given to the load on the cardiopulmonary system and quantity and types of fluid or food ingested, when engaging in physical exercise.