A person eats a meal and then immediately participates in a sprinting race. How might racing affect his digestion of the meal? His body will release acetylcholine, which will cause the release of digestive juices and slow digestion. His body will release acetylcholine, which will activate the muscles of the digestive organs and speed up digestion. His body will release adrenaline, which will decrease the flow of blood to the stomach and slow digestion. His body will release adrenaline, which will contract the muscles of the stomach and speed up digestion.