If you're sleep deprived, one of the best things you can do (counterintuitively) is high-intensity exercise. A few hours of sleep deprivation reduces insulin sensitivity and impairs cognitive function. But just 10 minutes of HIIT can enhance brain blood flow, cognitive performance, and blood glucose regulation. It can take you back to baseline, or even above it, for several hours or until you can get adequate sleep. You may not feel like going hard when you're tired, but the short-term benefits are real. Just don't make poor sleep a habit.