We all know good chemistry makes good relationships. But did you know chemistry has everything to do with having a good day—right down to thinking more clearly, getting more done and making meetings more productive?

Circadian rhythms are the patterns and clock cycles of living things. Our internal chronometer is made up of two tiny clusters of neurons called the suprachiasmatic nuclei. These sit behind our eyes in the hypothalamus and regulate the chemical factors that determine when we feel sharp or groggy.

This helps explain why good days start with recognizing and following patterns. Testosterone levels are highest in the morning, say 9am. This is the time for nervy, high energy activities. It’s the best time to answer emails, pitch ideas, plow through work and gain peer mindshare. Cortisol, a stress hormone, peaks in the morning too, then falls throughout the day. Just after lunch, say 1pm, is the right time for meetings utilizing your convivial, vivacious energy. Conversations tend to be more productive and less confrontational than in the morning. With this in mind, you might want to plan meetings in the afternoon as cortisol continues to fall off.

Melatonin, the hormone regulating the sleeping and waking cycles, is the third influencer. Levels top off in the morning, drop off from 11 am to 5pm and surge into the evening. Make use of creative time about 7pm, when melatonin begins seeping into your brain to prepare you for sleep. Evening is a good time for deep thought, close study and filing things away in long-term memory.

And don’t forget to get a good night’s sleep. You really need at least seven hours a night to fully replenish the chemicals in your batteries. An eight-hour slumber is even better.

Take a closer look at tomorrow. Maybe you should move that 9:30am meeting to 2pm and use your morning to jump start that presentation or project you’ve been putting off? Take heed of your chemistry and set yourself up for a good day.