The mystery of sleep is explored by scientists at UT Southwestern’s Peter O’Donnell Jr. Brain Institute and two other medical centers. Their study shows that a circadian clock protein in the muscle – BMAL1 – regulates the length and manner of sleep. The protein’s presence or absence in the brain had little effect on sleep recovery, while mice with higher levels of BMAL1 in their muscles recovered from sleep deprivation more quickly. Further, removing BMAL1 from the muscle severely disrupted normal sleep, leading to an increased need for sleep, deeper sleep, and a reduced ability to recover. The researchers expect the findings to eventually lead to therapies benefitting people in occupations requiring long stretches of wakefulness, such as the military or airline piloting. Assuming similar results are found in people as well as mice, new drug targets can be provided for the treatment of sleep disorders.