You want that increase in cortisol to happen early in the day. Basically you wake up because your temperature goes up. You're in what's called the circadian dead zone, which is the time in which light arriving at the eyes can do certain things but it can't time this pulse. That means that cortisol pulse is going to come in the afternoon, which means that your temperature rhythm is going to be shifted late. And that's actually a signature of depression and anxiety and difficulty falling asleep.