Do you often feel like you’re in a slump? If so, you might be fighting your inner body clock. Here’s the scoop from Psychology Today.

David Dinges is chief of the division of sleep and chronobiology at the University of Pennsylvania.
And he says whether you’re an early bird or a night owl affects much more than just the amount of coffee you need to start the day. He says the part of the brain that regulates your ability to think clearly and solve problems is heavily influenced by your body clock. Not only that, but studies continue to find that our body clock affects our moods, fitness habits, and it’s even linked to our personality!

For example, morning people tend to be introverts who are conscientious and driven, while night owls are more often impulsive extroverts. Owls are also more likely to be depressed.

Also, after waking up in the morning, early birds have higher levels the stress hormone cortisol than owls do, which is probably the reason for their instantly peppy demeanor – they’re already revved up. But owls’ heart rates are higher in the afternoon than in the morning, so they’re often sharper mentally and physically as the day goes on. And when it comes to our reaction times, we’re at our best when our body temperature peaks. For early birds, that’s 3:30 in the afternoon. For night owls, it’s 8 o’clock at night.