A report from Newsminer.com discusses the impact of sleep on self control and willpower.

Why can’t you resist temptation?

Surprisingly, the root of your problem may not be deficiencies in your willpower but instead lack of sleep.

Sleep has a profound influence on self-control, point out June Pilcher and her colleagues who published a 2015 study on the effects of sleep in the journal Frontiers in Human Neuroscience.