Sleep is important for good health. Getting enough sleep helps us learn, fight disease and avoid stress. Lack of sleep can cause problems with work, driving and social activities. It can also lead to health problems including obesity,heart problems. People with insomnia have trouble falling asleep, staying asleep or both. People with insomnia may become irritable and sleepy. They may develop headaches and have abdominal pain. Insomnia also can cause problems with concentration, memory and reaction time. This can make it dangerous to drive vehicles.