Summer Sunlight and Circadian Rhythms
How getting outside this summer is more important to your health than you may assume and the importance of circadian rhythms for long-term health.
As summer rolls around, people are starting to get a little pep in their step. You might think it’s because school is almost out, vacations are eminent, or the weather is a bit warmer, but in fact one of the biggest contributors to our enthusiasm this season is the increase in sunlight. On the flipside, our circadian rhythm is adjusted during this time due to longer exposure to light in the evening, which can actually harm our sleep and overall health. This week I wanted to dive into the importance of sunlight and adhering to our natural circadian rhythm for optimal health.
Sunlight is seemingly the simplest and most effective natural vitamin we can take. It has so many incredible health benefits. Sunlight is crucial for the synthesis of Vitamin D in the skin. Vitamin D is essential for bone health as it helps in the absorption of calcium and phosphorus. Adequate levels of Vitamin D can prevent conditions like osteoporosis and rickets. Sunlight also increases the release of serotonin, which is associated with mood elevation and helping you feel calm.
We’ve all heard of seasonal depression in the Pacific Northwest and Northeast due to lack of sunlight in winter months, but me being raised in Southern California, I didn’t believe it was real. I had a rude awakening when I moved to the East Coast for college and experienced this firsthand. The formal name for the ailment is Seasonal Affective Disorder or SAD for short, quite fitting given the constant gloomy weather tends to make everyone quite sad. It is categorized as a type of mild depression that occurs at certain times of the year, usually in the winter.
Some other benefits that are often overlooked are sunlight’s effect on the immune system, skin conditions, and cardiovascular health. Vitamin D plays a pivotal role in the immune system, enabling sunlight to help ward off infections. Controlled sunlight exposure can actually help treat certain skin conditions like psoriasis, eczema, and more. With regards to cardiovascular health, sunlight has been linked to lower blood pressure due to the release of nitric oxide in the blood from exposure to UV rays.
Most importantly, sunlight helps regulate the body’s circadian rhythm, improving sleep quality. Circadian rhythms are natural, internal processes that follow a roughly 24-hour cycle and are influenced by external cues such as light and darkness. These rhythms regulate various physiological and behavioral functions, including the sleep-wake cycle, hormone release, eating habits, and other bodily functions. Exposure to natural light during the day, especially in the morning, can help maintain a healthy sleep-wake cycle.
Since sunlight regulates our circadian rhythm it’s crucial that we treat sunlight like any other vitamin; something essential that we take every day. Exposure to sunlight in the morning signals the body to produce cortisol, promoting wakefulness and alertness, while also setting the timer for melatonin production to induce sleepiness once the evening rolls around and it’s time for bed. Waking up to the sun allows a natural light-dark cycle that enhances sleep quality, mood, and overall health by ensuring the body’s internal rhythm remain in sync with our external environment.
Your circadian rhythm acts as a master clock in the hypothalamus coordinating with all other biological clocks to keep your body on time. The most significant factor influencing circadian rhythm is light as it signals the brain when to wake up and when to sleep. Circadian rhythm also influences the production of hormones like melatonin and cortisol, which are crucial for sleep and stress responses.
Circadian rhythm is extremely important for sleep regulation as it plays a vital role in determining sleep patterns and the quality of sleep you are getting. Proper alignment of circadian rhythms with the natural day-night cycle leads to more restorative sleep, which is essential for overall health. There are various mental and physical health benefits to proper circadian rhythm.
Have you ever felt extremely drowsy and had severe brain fog after a horrible night’s sleep? Disruptions in circadian rhythm can affect mood and cognitive functions, leading to conditions such as depression and cognitive impairments. Research has consistently shown that disturbances in circadian rhythm can exacerbate or even trigger mental health disorders such as depression, anxiety, and bipolar disorder. Improper circadian rhythm also leads to poor metabolism and can affect weight management, appetite, and overall metabolic health.
Hormone regulation is also a key component of your circadian rhythm as certain hormones (melatonin and cortisol) follow circadian patterns. Circadian rhythm also affects other hormones related to growth, reproduction, and digestion, highlighting their comprehensive impact on bodily functions. There is also a correlation between immune function and circadian rhythm. Similar to sunlight, proper circadian rhythms enhance the immune system’s efficiency, helping the body to fight off infections and disease more effectively.
The prevalence of night shift jobs, jet lag, blue light from our devices, artificial light in homes and urban areas, 100-hour work week culture, and urban light pollution have all led to significant disruptions to our circadian rhythm. Studies suggest strong associations between circadian misalignment and mood disorders, such as depression and anxiety. Modern lifestyle changes, including excessive exposure to artificial light and irregular sleep patterns, have made it increasingly difficult to maintain synchronized circadian rhythm.
During summer, we tend to get more exposure to sunlight increasing our serotonin and energy levels, but the extended daylight can also harm our circadian rhythm by delaying the onset of melatonin production causing us to go to bed and wake up later. Warmer temperatures during the summer can also interfere with the body’s natural cooling process needed for sleep. Research indicates that people sleep on average 12 minutes less during summer. Summer can drastically affect our sleep length and quality making it extra important to listen to our bodies and prioritize rest during this time.
There are quite a few interventions for those who experience misalignments in their circadian rhythm. Cognitive behavioral therapy (CBT) can help address sleep disorders and prevent onset of co-occurring mental disorders cause by disruptions in circadian rhythm. Many wearable devices such as the Oura ring and Fitbit can track your circadian rhythm and provide insights into your sleep schedules. There are also light therapy treatments that adjust to individual circadian needs to help mitigate disruptions and ease SAD. The pharmaceutical industry has also begun to work on new drugs that target specific phases of the circadian cycle, while the OTC market for sleep aids like melatonin continues to grow. The more integrative and holistic approaches to syncing circadian rhythm incorporate mindfulness and meditation practices, like those Open provides, as well as the integration of chronobiology in treatment plans.
There are also several startups specifically working to provide accurate ways to manage your own circadian rhythm. Arcascope offers personalized sleep, food and caffeine timings for shift workers who suffer from misalignment, real time circadian tracking, and an open-source analysis platform for sleep and circadian data collected from wearables. Timeshifter is another platform in the space targeting jet lag and shift workers to help optimize circadian rhythms for peak performance and daily health.
This summer, I wanted to provide some tips and tricks to help resync your circadian rhythm while enjoying the long summer nights:
Gradually adjustment of sleep schedule: incrementally adjust your sleep and wake times to shift your circadian rhythm without drastic changes that may disturb sleep, maintain consistent sleep and wake times even on weekends or days off to help stabilize your circadian rhythm
Optimize light exposure: exposing yourself to natural sunlight after waking up to suppress melatonin and stimulate cortisol while limiting blue light exposure from screens for at least 2 hours before bedtime
If natural sunlight isn’t available there are many companies producing sunlight lamps that can help prevent SAD during winter months
Blue light glasses can also help ease the strain on your eyes from our devices
There are also alarm clocks that work to mimic the light cycles to help regulate our circadian rhythms
Diet and meal timing: align your mealtimes with your sleep schedule, eating earlier in the day can help advance your circadian rhythm while later meals tend to delay it, it’s also important to reduce caffeine and alcohol intake before bed, as they can disrupt sleep quality and alter circadian timing
Exercise appropriately: plan your workouts in the morning or early afternoon, avoid working out before bed due to overstimulation and disruptions in sleep
Create an optimal sleep environment: use blackout curtains, dimming lights, and keep the room cool to help you fall asleep and stay asleep
Establish a routine: establishing a nighttime routine can help train your body to know when it’s time to go to bed
Incorporate outdoor activities during the day: getting outside in the sunlight can help regulate your circadian rhythm and increase benefits form natural sun
Strategic napping: avoid long naps late in the day as they can disrupt your internal clock
Blue light management: turn devices to night mode or use blue light glasses if necessary to be online during late hours in the day
Sun exposure safety: make sure to wear sunglasses and sunscreen when going outside and optimize timing for when the UV rays are not as strong
The relationship between sunlight and circadian rhythm is a foundational aspect of human health. Misalignment of these rhythms, often due to inadequate sunlight exposure and modern lifestyle factors, can lead to various health disorders, including sleep disturbances, depression, and metabolic syndrome. It is extremely important to maintain healthy exposure to natural light and adhering to a regular sleep schedule aligned with natural light patterns for optimal health and well-being.
Great info!