02/03/2025
Cortisol, known by most as a stress hormone 😬, is a steroid hormone secreted by the adrenal glands (adrenal meaning: on top of your kidney) that helps to regulate our stress response and metabolic activity by suppressing inflammation, controlling blood sugar levels, regulating blood pressure, and utilizing fats and carbohydrates appropriately for metabolism.
Exercise is a potent stimulus for cortisol secretion. We actually want to encourage cortisol release at the appropriate times of day so that it isn’t chronically being released later due to build up of daily stress with no release valve. Studies show that exercise in the morning (around 7:00AM) produce the greatest cortisol spike and lasted 55 minutes longer than exercise done at the end of the day (7:00PM).
Some important points to consider:
👉 Although preference is important, exercise done in the morning when cortisol is at its all time high will improve sleep quality, blood sugar control, blood pressure regulation, and certain aspects of metabolism.
👉 Cortisol levels are highest in the hour after waking and gradually decrease throughout the day
👉 Morning exercise can boost wakefulness and cortisol secretion early in the day and increase growth hormone and melatonin production at night
👉 Some individuals may still prefer to exercise in the evening because their body is more primed for high intensity exercise
👉 It is usually a good idea to avoid intense exercise in the 3-6 hour window before bed as it can elevate core body temperatures, suppress melatonin, and disrupt sleep.
Cortisol levels will rise and fall with exercise regardless of timing, but if we time it to align with our natural circadian rhythm, we can increase the spike of cortisol when it’s supposed to be there and lower it throughout the day as we draw nearer to bed time.🥱 💤
