Cortisol
You’ve probably heard of the hormone cortisol. In everyday language, it’s often referred to—wrongly—as the stress hormone. After listening to a podcast by Dr. Andrew Huberman, I now understand where that misconception comes from. One of the primary functions of cortisol is to ensure your body has enough fuel (read: glucose) available during a stressful situation. So, it’s not a hormone that causes stress, but rather a substance that raises your blood sugar to provide your cells with the energy needed to handle stress effectively.
Origin
Cortisol is produced in the adrenal cortex. Here’s how that process works. When your brain perceives a stressful situation, the hypothalamus—a small structure deep in the brain—is activated to release corticotropin-releasing hormone (CRH). This hormone enters the bloodstream and travels to the pituitary gland, a pea-sized structure at the base of the brain. In response to CRH, the pituitary produces ACTH (adrenocorticotropic hormone), which is then sent via the bloodstream to the adrenal glands. These glands respond by producing and releasing cortisol into the blood.
Daily Rhythm
Now let’s look at how cortisol levels fluctuate over a 24-hour period. Unsurprisingly, cortisol levels are very low and stable during the first half of the night, when the body is in deep sleep and has minimal need for glucose. In the second half of the night, however, cortisol levels begin to rise rapidly. Alongside other mechanisms—such as the suppression of melatonin by light—elevated cortisol helps wake you up. The reason cortisol is so high upon waking is that getting up and starting the day requires a lot of energy. In physical terms, waking up is actually a stressful event for the body.
Tips & Tricks
In the first one to two hours after waking, cortisol levels in the blood continue to rise. After that, they gradually decline, reaching their lowest point in the late afternoon or early evening. This natural cortisol rhythm can be influenced—for better or worse—by your behavior. For example, doing an intense workout just before bedtime isn’t the best idea. Your body perceives the workout as a stressful event, which triggers cortisol production—exactly what you don’t want when you’re trying to fall asleep. On the other hand, an intense workout shortly after waking can extend the period of elevated cortisol, which is actually beneficial in the morning because it helps you feel alert and energized.
Another useful trick for positively influencing your cortisol rhythm is exposing your eyes to natural sunlight as soon as possible—ideally within the first hour after waking. Wearing glasses or contacts is fine, but leave your sunglasses off. Sunlight, like movement in the early morning, can slightly prolong the period of elevated cortisol. More importantly, it reinforces the body’s natural cortisol rhythm. In other words, it helps cortisol levels drop later in the morning, so that by evening you have enough sleep pressure to fall asleep easily.
My Daily Routines
Over the years, I’ve developed certain routines that positively influence my natural daily cortisol cycle. I have a consistent bedtime and wake-up time, which I rarely stray from. I also make sure to get at least eight hours of sleep each night. Three times a week, I take a cold shower in the morning right after waking up. The resulting stress response allows me to benefit from higher cortisol levels a bit longer—it gives me a real energy boost.
I love coffee—it’s another great energy booster—and I always start my day with it. However, I usually wait 30 to 60 minutes after waking before having my first cup. And after 10:00 a.m., I typically don’t drink coffee at all, so that the caffeine doesn’t interfere with the natural decline in cortisol. When possible, I enjoy my first cup of coffee in the sunshine. I also work out—both cardio and strength training—consistently in the morning before my first meal. Except on three days a week, when I do both: strength training before breakfast, followed by cardio either immediately after or later, depending on how energized I feel.
By late afternoon, I can feel my body starting to wind down for the night. Around 8:00 p.m., the sleep pressure is sometimes so strong that I doze off in front of the TV. I used to drink coffee at that hour, but now I stick to herbal tea with chamomile, valerian, and lavender. Beside that I also make sure to leave at least two—often three—hours between my last meal and bedtime. I haven’t had alcohol in over five years, and my sleep has improved significantly as a result.
Disclaimer
There are plenty of ways to influence your body’s cortisol rhythm. But please note: this blog is intended for informational purposes only and is not medical advice. If you have concerns about your health, always consult your doctor.