Researchers from the insomnia program at Northwestern Memorial Hospital in Evanston, Illinois determined that meditation can improve sleep quality. Participants who practiced deep relaxation exercises during the day were able to sleep more soundly at night. Insomnia is caused by elevated levels of activity or excitement during the day, preventing insomnia sufferers from sleeping soundly during the night. Practicing meditation reduces these levels of excitement and therefore improves sleep quality. Patients who suffered from chronic insomnia practiced meditation in the insomnia program and reported experiencing better sleep quality, including improvements in sleep latency, total sleep time, total wake time, and other sleep parameters.