Remember when you were a kid and fell asleep at the same time every night? You might want to start doing that again. A US study has revealed that people who sleep and wake at irregular times weigh more, are more likely to be stressed and depressed, have higher blood sugar and pressure and are at more risk of a heart attack. The next step is to figure out if sleep is the cause or effect. “From our study we can't conclude that sleep irregularity results in health risks, or whether health conditions affect sleep,” said lead author Dr Jessica Lunsford-Avery from the Duke University School of Medecine. “Perhaps there’s something about obesity that disrupts sleep regularity.” While more research is needed, the findings suggest tracking sleep regularity could help in predicting someone’s risk of heart and metabolic disease. That’s got to be worth an early night!