What is the Role of Circadian Rhythm in Hormone Balance & Weight Loss?

Do you often feel like your regular lack of sleep makes you feel agitated and hungry throughout the day? Are you wondering whether your stubborn weight gain has anything to do with your circadian rhythm? Don’t worry, we’re here to explain the connection between your body’s internal clock and your efforts to lose weight.

But before we dive into how your circadian rhythm affects your hormones and weight, let’s first explore what circadian rhythm is and how it helps your body function properly. So, grab a cup of delicious, herbal tea and read on to learn more about your body’s internal cycle! 

What is Circadian Rhythm?

Circadian rhythm is your body's 24-hour internal clock that keeps a track of your sleep and wake cycles. In other words, it is this cycle that ensures that you are awake during the day (when there is light outside), and asleep during the night (when it is dark outside). 

Light and darkness definitely play a crucial role in maintaining a regular circadian rhythm for every individual. This sleep-wake cycle also affects your physical and mental health, where a regular cycle ensures good overall health and mental wellbeing. 

Studies have shown that circadian rhythms are responsible for the physical, mental, and behavioral changes you experience throughout the day. Along with your sleeping patterns, this internal, natural rhythm also regulates your appetite, digestion, stress levels, hormones, and even your body’s temperature.

So, how does this internal system work? Well, studies have found that there is a master clock in your brain that affects several other biological clocks in your body, which are responsible for various bodily functions. Your circadian rhythm is one of these biological clocks, which receives signals from the master clock in your brain to produce sleep hormones. 

This sleep hormone is known as melatonin, which is released based on the amount of light that reaches your eyes. This is why your circadian rhythm promotes the production of melatonin in the evening since your master clock signals that there is less light in your surroundings. 

In fact, if you’re feeling low or experience a lack of energy some days without any particular reason, it may be possible that your biological clocks are disrupted. In other words, your master clock may be at odds with your circadian rhythm due to disruptions in your environment (i.e. night shift work, travel, time zone shifts, light from electronic devices, neurological diseases). And this dissonance can make you feel out of sync with your body.

Therefore, your circadian rhythm plays a detrimental role in your overall health. Any interruptions in your daily routine—or in the regular functioning of your body—can have a large impact on how your body performs throughout the day, which can ultimately affect your wellness goals.

How Does Circadian Rhythm Affect Your Hormones and Weight?

Now that we understand how circadian rhythm works, let’s take a closer look at the role it plays in balancing your hormones and the connection between circadian rhythm and weight loss.

As mentioned earlier, your circadian rhythm is responsible for regulating several essential hormones, which is why there is a large impact of sleep on weight management since fluctuations in your weight often occur due to hormonal imbalances (caused by a lack of sleep, among other factors).

So, let’s take a look at what these hormones are, their role in bodily functions, how they are affected by a disrupted circadian rhythm, and the impact this has on your weight loss journey:

Melatonin: 

Melatonin, as mentioned above, is a hormone that helps you sleep. It is released based on the 24-hour circadian rhythm, specifically, when less light reaches the eye. In simpler terms, more melatonin is released during the night than during the day on a regular circadian rhythm. 

For instance, when the weather changes and the sun sets earlier in the winter, you’ll probably start to get sleepy earlier as well. Most often, people think this happens, because it's cold outside and they want to get cozy in their bed. But, there’s a little more to that. This often happens because there’s less light in the environment. As stated earlier, when less light reaches your eye, your body begins the release of melatonin to help you sleep.

This means that factors like traveling to a different time zone or working in the night can disrupt your natural circadian rhythm, which affects both the production and the release of melatonin in the body. And your body isn’t sure when it’s time to relax and recharge.

This could also affect your appetite as you may be hungrier during the night rather than the day. Sometimes, this leads to cravings at night or “midnight snacking” as it is popularly termed, which further prevents you from falling asleep after consuming high-calorie, sugary foods. This can be detrimental to your weight loss journey, because you may be consuming more calories at night (when you won’t be using them). A consistent habit of unhealthy snacking can eventually lead to stubborn weight gain. 

Basically, when there are disruptions in your internal clock, your body doesn’t produce enough melatonin before you need to sleep, and this can cause issues in both the quantity and quality of sleep you’re getting every night. And a lack of proper sleep can lead to many health issues including, but not limited to, weight gain.

Cortisol: 

Cortisol is a stress hormone that helps your body prepare itself (both mentally and physically) for survival. Lack of sleep (through a disrupted circadian rhythm) promotes the growth of cortisol in the body—making your body think that there is some external danger—which is why you can’t relax. 

It’s important to note that high cortisol levels help prepare and fuel your body for situations where fight or flight is the only option. And when these cortisol levels are up, your body works to break down all of the available sugar and continually craves more to fuel that fight or flight mode. This particular function makes you crave more fattening, high-calorie, sugary foods that will help give you that boost of energy. 

Although this is great for when you are in true survival mode, consistently high cortisol levels can lead to irregular appetite, inflammation in the body, and eventually stubborn weight gain.

In fact, it’s challenging for your body to differentiate between mental and physical stress. So, even if you’re mentally stressed, your cortisol levels will still go up trying to prepare your body for survival, and overtime you’ll get stuck in this survival mode. 

On top of that, when you consume these sugary, fattening foods, you’re not necessarily using up those calories for survival as your body intended, since the stress is not physical (it’s a mental stress). As a result, those calories will contribute to fat deposits in your body not only making you gain that weight, but also making it more challenging than ever to lose it. 

Leptin:

Leptin is a hormone that is responsible for regulating your appetite; it’s also known as a “satiety hormone” since it lets your brain know when you’ve had enough food to eat. 

As you can probably guess, this hormone plays a crucial role in your weight management, because if your brain is receiving timely signals of when you are satiated, then you likely won’t overeat. 

But, the problem occurs when these signals aren’t operating correctly. In other words, disruptions in your circadian rhythm can slow the release of leptin in the body. For instance, if you work the night shift, then your circadian rhythm undergoes irregularity, and your brain struggles to determine when it’s time to wake up and eat versus when it’s time to sleep. 

This irregularity shows up in your appetite as you may feel constantly hungry and never satisfied since your brain isn’t getting the appropriate satiety signals (leptin resistance). As a result, you might begin to feel like you need to eat or snack on something constantly to feel energized, which can lead to weight gain and eventually other issues like heart disease and obesity.

Ghrelin:

Ghrelin is also another hormone that is known for its role in appetite regulation. It’s usually termed as the “hunger hormone” since its release determines that your stomach is empty and needs to be fed.

Most weight loss regimes aim to decrease the release of ghrelin and increase the release of leptin, so that those suffering from appetite irregularity and stubborn weight gain can work towards sustainable weight loss. 

This mission is difficult, however, if the reason for the imbalance of leptin and ghrelin is a disruption in the circadian rhythm. Your circadian rhythm irregularity can increase the release of ghrelin in an attempt to provide more energy to the body. 

Eventually, your body does not recognize that it’s well-fed and continues to crave for more food, which can lead to an over consumption of calories, weight gain, and even obesity.

Conclusion

Overall, your circadian rhythm is responsible for many functions in the body. It’s more than just a 24-hour sleep-wake cycle; it’s a regulatory system for your hormonal health, weight management, and your overall wellness.

Therefore, it’s important to ensure that you take care of your circadian rhythm by doing whatever is in your control to get a good amount of quality sleep every night. This is not only for giving your body a chance to relax and recharge to take on the next day, but also for providing a proper sleep-wake cycle that maintains harmony in various bodily functions.