How Sleep and Wake Cycles Affect Your Mood

As the seasons start to shift, many of us may feel a change in our sleep patterns — and our mood. With shorter days and longer nights, it can be tough to maintain a consistent sleep routine. While many believe sleep is crucial for our health and well-being, it often ends up on the back burner when life gets busy.

This time of year, filled with hectic schedules and added stress, can make it even harder to prioritize getting enough rest. But understanding the science behind our sleep-wake cycle can help us appreciate why sleep matters so much, even when life feels demanding.

In this article, we’ll dive into how our sleep-wake cycle impacts our mood and share some practical tips to help you enjoy more restful sleep at night.

What is the sleep-wake cycle?

The sleep-wake cycle, also known as the circadian rhythm, is your body’s natural clock. It regulates our daily rhythms of alertness and sleep over each 24-hour period. The circadian rhythm also plays a role in things like appetite, digestion, and hormone release. Humans aren’t the only species to have a circadian rhythm — almost every living thing has some sort of circadian rhythm, including plants, animals, and even microorganisms.

Your sleep-wake cycle responds to environmental cues like light and temperature, which help you feel more alert during the day and ready for rest at night. It’s managed by a small part of the brain called the suprachiasmatic nucleus (SCN), located in the hypothalamus.

The sleep-wake cycle depends on a complex balance of hormones, especially melatonin and cortisol. As evening approaches and light fades, melatonin levels rise to prepare the body for sleep. Cortisol levels peak in the morning to promote wakefulness and energy. Keeping this natural rhythm steady supports not just physical health but also mood and mental clarity.

When this rhythm falls out of sync — whether it’s from shift work, travel across time zones, or just an irregular sleep schedule — it can disrupt this natural balance. These disruptions can make it harder to focus, impact judgment, and increase emotional sensitivity. 

Research shows that ongoing disturbances to the circadian rhythm are linked to mental health disorders, including depression and anxiety. For example, studies suggest that shift workers — who tend to have inconsistent sleep schedules — often report higher stress levels and worse mood.

Can sleep affect our mood?

Getting quality sleep each night is an essential part of maintaining good mental health. Scientists are still learning more, but there are brain functions that can only happen while you’re sleeping. When you get enough quality sleep at night, you help your brain work well while you’re awake. On the flip side, being sleep-deprived may lead to irritability, stress, and even contribute to mood disorders like depression and anxiety.

The connection between sleep and your mental health

Sleep profoundly influences our mental health through a combination of physiological and psychological mechanisms. Scientists are still trying to understand why, exactly, we need to sleep. But they do know that sleep facilitates crucial processes that restore the brain and regulate emotions, many of which only happen while we’re asleep.

There are two broad categories of sleep: REM (Rapid Eye Movement) and non-REM sleep. They both play distinct roles in emotional regulation.

During REM sleep, your brain sorts through emotional experiences and memories, which reduces emotional distress and builds resilience. This stage is important for managing complex feelings and keeping emotional reactions in check.

On the other hand, non-REM sleep, especially the deeper stages, is essential for recharging your body and mind. It restores physical energy, supports your mood, and strengthens your ability to think clearly, which promotes balance and focus throughout the day.

Quality sleep is also important to help your brain to:

• Strengthen working memory
• Repair and maintain neural connections
• Process and regulate emotions
• Clear out “brain waste” by removing unimportant information
• Consolidate new learning and insights
• Support immune response and stress management

Sleep and mood disorders

Sleep problems and mood disorders, like bipolar disorder, share a complex and often intertwined relationship, which means that each may affect the other. 

Being sleep-deprived can make mood disorders worse and can even trigger manic episodes. Additionally, living with a mood disorder can make it much more difficult to get quality sleep. 

In depression, for example, individuals often experience insomnia or early morning awakenings, which can intensify feelings of fatigue, despair, and hopelessness during the day. Other people with depression can experience hypersomnia, or sleeping too much — which can lead to increased lethargy and disinterest in daily activities. 

People in manic episodes experience a decreased need for sleep, which if prolonged is formally recognized as one in a group of symptoms of bipolar disorder. Not sleeping for days may heighten impacts of mania, after which some people may experience a crash into the opposite mood – a depressive episode involving days of increased sleep.

Sleep disturbances are the most commonly reported symptom of depression, and research has found that up to 90% of people with depression get poor quality sleep. Sleep problems have also been linked to more severe depression symptoms and a higher risk of suicide.

How the seasons affect sleep-wake cycles

Seasonal changes can have a big impact on your sleep-wake cycle, especially if you live in an area (like Northern states) with more drastic changes in daylight hours throughout the year. 

Our bodies rely on natural light to keep our circadian rhythms in sync with the 24-hour day. With fewer hours of sunlight in the winter, the circadian rhythm can get out of sync — which makes waking up and going to sleep at regular times harder and leaves many people feeling tired, foggy, or just “off.” 

For some people, this shift in light can even contribute to Seasonal Affective Disorder (SAD), a mental health condition where you experience depression or mania in response to seasonal changes.

Melatonin, the hormone that makes us feel ready for sleep, depends on light cues, and are released during darkness. When there’s less light in winter, melatonin levels may stay higher in the morning, which can cause daytime drowsiness, or rise early in the evening, which can make people feel sluggish. 

Light exposure also influences serotonin—a neurotransmitter tied to happiness and energy. Less sunlight in winter may lower serotonin levels, which often reduces energy and makes people feel emotionally sensitive.

Tips for getting quality sleep

Getting a good night's sleep can make a big difference in how you feel each day, and there are simple steps you can take to improve your sleep quality. 

Here are some tips to help you achieve restful sleep:

1. Get sunlight during the day: Exposure to natural light during the day helps regulate your circadian rhythm and can lead to better sleep at night. Try to spend at least 20 to 30 minutes outdoors, especially in the morning. Even sitting by a window with natural light can have positive effects. If you live somewhere with very dark winters, try a light therapy box.
2. Regular exercise: Engaging in physical activity can help you sleep better and for longer. Aim for at least 30 minutes of moderate exercise most days — but it's best to avoid vigorous workouts close to bedtime, as they can energize your body and make it harder to wind down afterwards. Gentle activities like yoga or stretching in the evening can also help relax your muscles and prepare your body for rest.
3. Be mindful of caffeine consumption: Consuming caffeine in the afternoon or evening can disrupt your ability to fall asleep. Try to limit your intake to morning hours and consider switching to decaffeinated beverages in the afternoon. Remember that caffeine can linger in your system for several hours.
4. Reduce irregular or long naps: While napping can help replenish energy, taking long or irregular naps during the day can interfere with nighttime sleep. If you feel the need to nap, aim for short naps of 20 to 30 minutes in the early afternoon. This approach can boost your mood and alertness during the day without disrupting your nighttime rest.
5. Refrain from using electronics before bed: The blue light emitted by phones and computers can inhibit the production of melatonin, the hormone that facilitates sleep. Try to power down electronic devices at least an hour before bedtime. Instead, engage in relaxing activities that don’t involve screens, such as reading a physical book, journaling, or practicing deep breathing exercises.
6. Set up a night routine: Establish a calming pre-sleep routine to signal to your body that it’s time to wind down. This could include activities like reading, meditating, or taking a warm bath. Consider dimming the lights in your home during this time to further signal your brain that bedtime is approaching. Creating a consistent routine helps your body recognize when it's time to sleep, and makes it easier to relax and transition into a restful state. 

Seek professional support

If you’ve tried improving your sleep habits but still struggle with sleep issues or feel like your sleep-wake cycle is out-of-sync, reaching out to a professional can provide valuable guidance. A mental health expert can offer insights into your symptoms and provide helpful, evidence-backed support.

Rule out a sleep disorder

If you’re struggling with sleep issues even after practicing good sleep hygiene, it’s essential to consult with a healthcare provider to identify any underlying sleep disorders. Conditions like sleep apnea or insomnia can disrupt your sleep patterns and have a significant impact on your mental health. 

A professional can assess your symptoms and discuss tests or evaluations to pinpoint any specific concerns. Difficulties may persist or worsen if these underlying disorders are not identified and addressed.

How mental health treatment can help

Fortunately, when it comes to improving sleep, there are several therapeutic approaches and medications that you and a mental health professional can explore:

• Cognitive-Behavioral Therapy for Insomnia (CBT-I) targets the thoughts and behaviors that interfere with your sleep. This structured program can help you develop healthier sleep patterns and identify, and change, the unhelpful thinking patterns that make both insomnia and depression worse.
• Mindfulness-based therapies focus on relaxation techniques that promote better sleep by reducing anxiety and stress.
• Other therapeutic approaches, such as acceptance and commitment therapy (ACT), can also help address sleep-related issues.
• Medications may offer short-term relief for sleep disturbances. Antidepressant medication can also treat any depression symptoms that could be making your sleep troubles worse.

Get mental health support with Cerebral!

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