Before we begin to answer the question of how your chronotype affects your hormones, let’s define chronotype. This term refers to your natural sleep inclinations and schedule. There are morning types, who identify as “morning people,” and there are evening types, who are more inclined to stay up late and sleep in.
Evening types normally have sleep-wake cycles that begin two to three hours later in the evening than morning types. Morning types get up with the sun and fall asleep within a few hours of dusk, while evening types fall asleep 5-6 hours after sunset and get up a few hours after dawn. Morning types do their best work early in the daytime. Evening types may have a surge of energy and creativity after dusk. Extremes outside the normal range can cause a person difficulty participating in routine work, school, and social activities.
Hormones are affected by your chronotype because some of your hormones follow a circadian rhythm.
Your adrenal hormones follow these circadian rhythms – mainly cortisol and DHEA, insulin production, and prolactin production. While most laboratories base hormonal norms on morning types, measuring cortisol at 8 am and 4 pm, evening types’ hormones may measure out of “norms” and not be abnormal.
If you naturally wake up at dawn, your melatonin levels have dropped, and your insulin levels will rise. Your fasting blood sugar is low, and your hypothalamus needs glucose to function, which triggers a surge in cortisol. Cortisol releases stored sugar before you break your fast, and your hypothalamus produces dopamine, waking up your brain and turning off prolactin. Prolactin is your other nocturnal hormone that follows melatonin by about three hours. This means you’ll have low daytime levels about three hours after dawn. Elevated prolactin during the day blocks the receptor sites for steroid hormones, including sex and adrenal hormones. Checking your prolactin between 8-9 am helps to determine if your circadian rhythm is regular. However, if you’re an evening type, it may be best to check your morning prolactin 3 hours after you naturally wake up.
Many people can adapt their body rhythms to their life and work schedules, but they may need chemical help.
Either in the form of medication or herbals, to get them to sleep or wake up. For instance, evening types typically depend on caffeine to stimulate dopamine production and wake up.
Knowing your chronotype is useful, but it’s also good to know that your chronotype can be adapted. While you’re born with a chronotype tendency, how you were raised can solidify in your chronotype. If you need or want to, you can adapt your chronotype over time to match your work and lifestyle.
If you have questions about chronotype and hormones, please join me in my Hormone Support Group. You can get access to Hormone Reboot Training.