Sleep quality has been linked with everything from diet and exercise to electronic screen use, and now a new study suggests that something a little less tangible may play a role: A sense of purpose. The finding could be especially important for older adults, the researchers say, since insomnia and other sleep problems tend to increase with age. Doctors prefer to treat these issues without pharmaceuticals, when possible, and this study may suggest that having a good reason to get up every morning may help in that regard.