Currently, it is not known if the amount of nighttime sleep has any effect on the overall physical fitness, and on how much energy do people who have a relative with type 2 diabetes (parent, sibling, or grandparent) use to perform activities of daily living. This study will test the hypothesis that individual differences in nighttime sleep duration are related to differences in the amount of energy used to perform activities of daily living and the overall level of physical fitness of the individual.