How to Optimize Your Circadian Rhythm This Winter

Got the winter blues?

You’re not alone! The colder temperatures combined with less daylight hours interfere with the body's circadian rhythm, your natural internal “clock” that regulates everything from energy and sleeping patterns to mood and appetite. With less sunlight and more time spent inside, a variety of biological and physiological changes in the body disrupt normal function, such as causing a reduction in serotonin – the happiness hormone – and suppression of melatonin – the hormone that helps you fall asleep with ease.

The body is an interconnected system, with each organ, metabolic pathway, and bodily function playing a role in overall health. When your hormones are imbalanced, especially the ones that regulate mood and sleep, your metabolism, digestion, and mental health may suffer as well.

Seasonal affective disorder (SAD) is common during this time of year, with symptoms such as feeling depressed, difficulty concentrating, problems falling or staying asleep, low energy, and feeling sluggish or agitated. By recognizing these symptoms, you can take action to reset your internal clock and prioritize self-care measures that calibrate your health inside and out. If symptoms persist, speaking with your healthcare provider as well as a mental health professional can help you manage your symptoms and find relief.

How does your body’s internal clock work?

Your circadian rhythm operates on a 24-hour cycle, and it doesn’t just impact how you wake up and fall asleep – it also helps maintain body temperature and proper digestion. This internal clock is regulated by a group of neurons in the hypothalamus that make up the suprachiasmatic nucleus (SCN), which functions according to light and environmental cues. This is why it feels natural to wake up with sunrise and fall asleep when it gets dark!

The SCN is responsible for releasing hormones, like cortisol, that help you snap awake and become alert. The SCN also takes cues from the environment to regulate your internal temperature, helping you warm up as you wake up and cool down at night, which is why keeping a cool room is often touted for its sleep-promoting benefits!

Syncing your body clock with the seasons or optimizing your wake/sleep cycle might seem daunting, but starting with a few key lifestyle changes that address these issues can help you better endure the winter months.

Five ways to optimize your circadian rhythm this winter season:

1. Keep a consistent bedtime.

Create a bedtime routine that lets your body know it’s time to wind down, whether it’s a hot cup of tea, a good book, or putting your phone away at least an hour before bedtime. Your internal clock functions best when your body senses a regular routine, so it’s important to find a healthy sleep rhythm by waking up and going to bed at the same time each day (or as close to the same time as possible). Taking melatonin at bedtime may also be helpful if it’s hard to fall asleep, but as always, check with your healthcare provider before beginning a new supplement routine.

2. Exercise more.

A good sweat not only ramps up your heart rate and strengthens the cardiovascular system but can also help you sleep more soundly. Research from the University of Southern Queensland in Australia demonstrated exercise, specifically strength training, improved sleep quality in participants compared to those who did no strength training at all. Exercise increases serotonin in the brain, which can help the mental health symptoms a person may experience if suffering from SAD.

To help your body find balance between your active and resting hours, set up a regular workout routine, whether in the morning before work, midday during your lunch break, or after work as a way to de-stress from the day. Setting up this regular routine will help your body’s clock better determine when it’s time to wake up, eat, release essential hormones, and get to bed.

Be careful not to exercise within 1–2 hours of bedtime, though, as this can be too stimulating and make it difficult to get a good night’s sleep. However, bio-individuality – the IIN concept that means we all thrive with different diets, workouts, and lifestyles – is key, so do what works best for you! 

3. Limit your caffeine intake.

While a morning espresso can give you a jolt of energy on groggier mornings, too much caffeine (especially late in the day) can harm your circadian rhythm in the long term. Caffeine is a stimulant that delays the secretion of melatonin, the natural sleep hormone made in the pineal gland in the brain. Many people metabolize caffeine differently, but in general, limiting caffeinated coffee to the morning hours is recommended because of caffeine’s effect on melatonin production.

As an alternative, you can swap coffee for other options that still have caffeine but may not impact your sleep so greatly. These include:

• Matcha – The green tea’s entire leaf is ground up and brewed into a powder, high in antioxidants and amino acids. It also contains L-theanine, an amino acid that promotes a state of calm without drowsiness that may relieve those jittery feelings you get with coffee.
• Green tea – Made from the same plant as matcha, green tea has considerably less caffeine per serving and also contains L-theanine. Green tea contains antioxidants, such as epigallocatechin gallate, that play a role in preventing free radical damage and aging.
• L-tyrosine – This amino acid and stimulant, known to help with alertness and focus, provides the same feelings you get when you consume caffeine, without the jitters or addictive quality.

4. Try intermittent fasting.

Intermittent fasting is practiced by intentionally spreading out meals at certain intervals to allow your body to experience an extended fast between dinner and breakfast. At its simplest, it could look like 12 hours between dinner and breakfast (7pm to 7am), which is manageable for many.

There are many benefits to intermittent fasting, specifically one type of fasting called early time-restricted feeding, which involves eating only in a particular window of the day, such as 7am to 3pm, and fasting from 3pm to 7am the following day (a 16-hour fast). In a study of men with prediabetes, researchers found this type of fasting improved insulin sensitivity, lowered blood pressure, and facilitated weight loss.

What does this have to do with your circadian rhythm? The same light and environmental cues that tell you when it's time to wake up and go to sleep also cue the hormones that regulate appetite, digestion, and metabolism! By syncing your eating schedule with your waking schedule, you’ll not only promote a more in tune circadian rhythm, but also promote sleep quality and encourage appropriate hunger cues, both of which go a long way in terms of your overall health. 

5. Use light therapy.

Sunlight is key to managing your circadian rhythm! Remember the SCN? These neurons are responsible for signaling when it’s time to wake or sleep. But during the winter months, we have less available sunlight hours, and that’s if the weather cooperates! On cold, gray, and cloudy days, it can feel even harder to be awake and energized, so light therapy can come in handy, especially for those who experience SAD.

Light therapy boxes mimic natural light and thus ease symptoms of sadness, anxiety, and depression by stimulating the hypothalamus (and SCN) and providing the light required by your internal clock. Consult with your doctor to determine if light therapy is safe for your health and meets your needs.

Watch your mental health carefully.

Because mental health is closely tied to the health of your circadian rhythm, creating healthy habits that promote an in sync and in tune internal clock can be beneficial for your mental and emotional well-being. Experiencing occasional moodiness or fatigue is different from experiencing SAD, which is punctuated by continuous feelings of depression and low mood.

The winter season can be tough on anyone, especially during a global pandemic that has exacerbated isolation and loneliness. Implementing small yet sustainable changes to your routine, such as going to bed 30 minutes earlier each night or trying to get outside each day for 10 minutes of sunshine, will impact your health in both the short and long term. If, despite self-care measures and changes to your lifestyle, you still experience symptoms of SAD, seek guidance from a mental health professional, such as a therapist or counselor.