Sunlight and Circadian Rhythm: The Foundations of Hormonal Health

When it comes to hormonal health, many people instinctively focus on diet and supplementation. While these factors are undoubtedly important, they shouldn’t be our starting point.

Before delving into dietary choices, we must first examine our light environment—our true foundation for hormonal balance.

Light carries vital information that communicates with our brain, triggering hormonal responses that align with the time of day. Essentially, our hormones reflect the signals we receive from our environment. If your hormones are out of balance, it’s time to reassess the signals you’re sending to your body.

Two primary hormones that fluctuate throughout the day are cortisol and melatonin.

Let’s explore how these hormones influence our bodily processes from dawn to dusk.

Cortisol peaks at dawn, waking us from sleep. Our bodies are designed to respond to the morning light, which our eyes interpret as a signal to begin the day. However, barriers like sunglasses or windows can obscure this essential message. To kickstart our hormonal balance, it’s crucial to expose our naked eyes to natural light in the morning. This morning sunlight communicates with the mitochondria in our adrenal glands, prompting the conversion of cholesterol into pregnenolone—the so-called "master hormone." In the early hours, much of this pregnenolone is transformed into cortisol, which then signals every cell in our body that the day has begun.

The body’s perception of stress also plays a crucial role in hormone conversion when we start our day. While some pregnenolone is directed toward cortisol production, the remainder can be converted into sex hormones like progesterone, estrogen, testosterone, and DHEA. To maintain a healthy balance, it’s important to foster a state of calm. Engaging with natural light shortly after sunrise—ideally within the first hour—can help signal to your body that it is safe and relaxed. Bonus points if you connect your bare feet to the earth! This preserves pregnenolone for sex hormone production. In contrast, immediately checking your phone or diving into your email can induce stress, prompting your body to prioritize cortisol over sex hormones.

As the sun climbs higher, UVB and UVA rays become more prominent. Midday UVB light is vital for hormonal health, allowing hormones to circulate freely in the bloodstream without needing a carrier. This helps the body assess its hormonal levels and, if necessary, directs excess hormones to the liver for elimination. Additionally, UVB light aids in Vitamin D production, another crucial component of hormonal health. Aim for at least 20 minutes of midday sunlight on your skin—start slowly if you’re not used to sun exposure—to support your circadian health.

As sunset approaches, our bodies prepare for darkness. This darkness signals the pineal gland to produce melatonin, promoting sleep and activating repair processes. Unfortunately, exposure to artificial light at night can inhibit melatonin production, leading to increased cortisol levels. This misalignment can disrupt our natural hormonal rhythms, contributing to issues such as hormone-related cancers and metabolic dysfunction.

Two other hormones significantly influenced by circadian rhythms are thyroid hormones and leptin. 

Thyroid hormones follow their own circadian cycle, with peaks and troughs throughout the day. Research shows that disrupted circadian rhythms can flatten these patterns, impairing metabolic communication within our tissues.

Leptin, released after meals, informs the brain about our energy reserves, helping it determine hunger levels. At night, leptin downloads this information into the brain, signaling that we don’t need additional food. This circadian-based process also impacts sex hormone production the following day. If leptin fails to complete this download, it may misinterpret the body’s energy state, leading to a down-regulation of non-essential hormones like sex hormones. Essentially, if your body feels it’s in a state of scarcity, it prioritizes cortisol over sex hormones, affecting processes like ovulation and pregnancy.

In summary, maintaining a healthy circadian rhythm is essential for optimal hormonal health. When you prioritize your light exposure and circadian signals, all other aspects of health—diet, supplements, exercise—will naturally improve.

Need help implementing some of these practices into your daily routine? I’m here to help! Book a free discovery call - let’s chat about how we can work together to achieve your hormonal health goals.