People with exercise-induced asthma may have more symptoms when they exercise at night as opposed to in the morning, according to findings in the Journal of Allergy and Clinical Immunology. A group of 22 people with asthma and a group of 12 healthy controls underwent exercise tests at 7 AM and 6 PM. In the asthma group, the severity of exercise-induced bronchospasm was significantly higher at night than in the morning, and the minute ventilation during exercise was significantly lower at night than in the morning. The asthma group also experienced a greater fall in forced expiratory volume in 1 second (FEV1) following exercise at night than in the morning. In contrast, the control group showed no change in FEV1 fall or minute ventilation during exercise.