How Circadian Rhythms Impact Sleep, Hormones, and Metabolism

Sleeping with book on face. Image - Pexels: Deniz Kyzyltoprak

If your typical day is packed with meetings and deadlines, or you need constant traveling, other people think you have everything under control. But inside you, you are actually struggling to stay energetic and sharp. Your energy levels are irregular, your mood swings are unpredictable, and you often find yourself staring at the ceiling at 3 a.m., unable to sleep. Waking up after just a few hours of restless sleep, only to face a day packed with demanding meetings and critical decisions to make.

Your brain feels foggy, your patience is thin, and every task seems significant.

If it sounds like you, poor sleep isn’t just a minor issue, it’s a serious issue that can affect your performance and overall health. Over time, it can also lead to metabolic disorders like insulin resistance and weight gain even if you are dieting. Lack of sleep can also affect your adrenal glands, which play a crucial role in managing stress and regulating hormones.

Circadian Rhythm: Sleep-wake cycle

The root cause is in the disruption of your circadian rhythm, the 24-hour cycle in our brain that regulates cycles of alertness and sleepiness by responding to light changes in our environment. This rhythm, governed by the circadian clock in the brain, aligns with environmental cues like light and temperature.

When these cues are disturbed by late-night work, constant travel across time zones, or irregular sleep-wake cycles, your body’s function is off balance. Staying up late and sleeping in on weekends can cause a mismatch with your weekday schedule, leading to circadian rhythm disruption.

Regular social jet lag can lead to sleep deprivation, weight gain, mood disorders, and increased risk of health problems like obesity, metabolic disorders such as insulin resistance, and heart disease. Work schedules, social activities, and lifestyle choices lead to irregular sleep patterns, creating environmental factors that affect your body’s circadian rhythm.

The Role of Hormones & Metabolism: Your hunger cues

Lack of sleep affects your hormones, especially the imbalance of ghrelin and leptin, hormones that signal hunger and fullness, can lead to overeating and weight gain even if you are eating less. Sleep is essential to regulating the hormones that affect hunger and appetite. Poor sleep can lower your metabolism, making it harder to burn calories. Establishing healthy sleep habits can support your weight loss efforts. Sleep quality also affects other hormone levels that regulate stress, blood pressure, and even your menstrual cycle. By improving your sleep, you can restore this balance to prevent many diet-related and hormonal diseases.

Your Mental Health: Lowering your emotional intelligence

NHLBI, the nation’s leader in the prevention and treatment of heart, lung, blood, and sleep disorders has a study that shows that sleep deficiency changes activity in some parts of the brain. If you’re sleep-deprived, you are more likely to have trouble making decisions, solving problems, controlling your emotions and behavior, and coping with change. Sleep deficiency has also been linked to depression, suicide, and risk-taking behavior.

3 Tips to Master Your Sleep (In Any Situation):

1. Creating the Perfect Sleep Environment

Start optimizing your sleep hygiene tonight, the first thing you can do tonight is transform your bedroom into a sleep sanctuary, like a cave. It’s dark, cool, and quiet.

2. Pre-Sleep Routines and Diet

Adjust your pre-sleep routine. Instead of taking a hot shower right before bed, which can raise your body temperature, shower 1–2 hours earlier, giving your body time to cool down naturally. Avoid heavy, fatty, or sugary snacks close to bedtime, as they can disrupt your sleep-wake cycle.

Opt for light snacks like oats and milk or cottage cheese with berries or nuts, balancing your food intake and helping you sleep better. The perfect formula for a pre-sleep light snack is 50% complex carbs and 50% lean protein, it helps you stay fuller until your breakfast.

3. Calming a Racing Mind

One of your biggest challenges might be calming your mind before bed. The reason is your racing thoughts, your mind involuntarily digs up random thoughts and memories and moves rapidly from one to another.

To prevent this, you can start a new routine of spending 10 minutes in dim light, processing your thoughts outside of bed. Sleep hygiene, stretching, journaling, or writing a to-do list for the next day can help clear your mind, making it easier to fall asleep.

Tips for Night Shift Workers

Working night shifts or irregular hours can be challenging for maintaining good sleep and avoiding sleep deprivation. Here are two tips to help shift workers manage their sleep better:

1. Stick to the same sleep schedule (even on days off)

Try to go to bed and wake up at the same times every day, even on days off, it helps regulate your circadian rhythm. If you can’t get enough sleep in one go, consider taking short naps (20–30 minutes) during your shift breaks to reduce sleep debt.

2. Avoid daytime sunlight before sleep

Exposure to natural light during your working hours can help you stay awake, but avoid it close to your bedtime as it can disrupt your circadian rhythm. During your shift, use bright lights to stay alert. On your way home, wear sunglasses to minimize light exposure, signaling to your body that it’s time to wind down. Use blue light-blocking glasses or apps on your devices to reduce exposure to blue light before sleeping.

Tips for Work Traveling & Vacation

If you’re working in a job that requires you to travel often or you’re going for a vacation from another side of the world, maintaining your sleep is not easy, however you can minimize its impact on your circadian rhythm. Traveling can mess up your circadian rhythm and sleep-wake cycle, that’s why you’ll have jet lag or social jetlag. When your body’s internal clock (circadian rhythm) doesn’t match your social schedule. This often happens when you have different sleep patterns on weekdays and weekends.

Here are some simple tips and reasons why they help keep good sleep quality before, during, and after flights:

Pre-Flight Tips

1. Adjust sleep schedule in advance

Gradually shifting your sleep schedule helps your internal clock adjust to the new time zone, reducing circadian rhythm disruption.

2. Sleep early

Starting your trip well-rested helps avoid sleep deprivation, which can worsen jet lag and impact your overall health, so if you know you’re traveling the next day, sleep 1 or 2 hours earlier.

3. Pack early

Reducing pre-travel stress ensures better sleep quality the night before, preventing poor sleep from last-minute packing.

4. Eat light

A light meal before flying prevents discomfort and supports good sleep quality by avoiding heavy, fatty foods that can disrupt food intake and insulin sensitivity.

During your travel: In-Flight Tips

1. Stay hydrated

Airplane cabins are dry, and staying hydrated helps prevent fatigue and maintain overall health.

2. Invest in a sleep kit

Use an eye mask or sunglasses to block out artificial light, ear plug to cancel the noise, helps signal to your body that it’s time to sleep, aiding in maintaining your circadian rhythm.

3. Avoid alcohol and caffeine

Both substances can cause circadian disruption and make it difficult to sleep, worsening jet lag.

Post-Flight Tips

1. Get natural light

Exposure to daylight helps reset your circadian rhythm, signaling to your body when it’s time to be awake and when it’s time to sleep.

2. Stay awake until bedtime (as much as you can)

Staying awake until local bedtime helps your body adjust to the new time zone, reducing the effects of social jet lag.

3. Take naps

Short naps (20–30 minutes) can refresh you without interfering with your regular sleep cycle, preventing prolonged circadian disruption.

4. Jetlag Apps

Apps like Timeshifter, Entrain, and Uplift help your internal clock adjust to new time zones.

Final Thoughts

Sleep isn’t just the end of the day; it’s the beginning of tomorrow. For busy people like you, paying attention to the circadian rhythm and making small changes can lead to significant improvements in sleep quality and overall health. Whether it’s creating a better sleep environment, adjusting your diet, or managing your pre-sleep routine, every little step counts. Something you already possess that is free, healthy, and safe, and that will help you think clearly, make better decisions, be in a better mood, and be more productive and effective than anything else, is tonight, a good sleep.


Here Are Three Ways I Can Help:

  1. Join my free webinar to achieve how to eat healthy with a busy schedule in any situation.
  2. If you are not sure where to start, download the No BS Nutrition Framework to navigate and maintain your health with food, download here.
  3. If you’re an entrepreneur who wants real, lasting results with a sustainable approach and who wants to take back control of their health, you can join our 6-Week Challenge. After the challenge, you don’t need another health-related program anymore, and you’ll get the promised outcome when you commit, and committing to this challenge is easy and fun that you’ve never experienced before, so let’s talk now.
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