How to fix constipation with circadian rhythms

How to fix constipation? It’s a question that people with constipation would love to know the answer to. I know many people look to motility aids as a means to address it. But the problem with this approach is that it focuses on a symptom rather than the underlying cause of the problem.

As a result, some get temporary relief. But by ignoring the cause, other problems pop up down the road. Identifying the underlying cause corrects the problem.

The first step in understanding constipation is that it’s a problem with motility in the colon. Motility in the colon is separate from the small intestine. Many try addressing the migrating motor complex(MMC) to improve constipation.

But the MMC is a motility program in the small intestine. It doesn’t have anything directly to do with motility in the colon. Once food enters the colon the MMC is over, so to speak.

Now that we know we want to focus on colon motility, let’s look at how colon motility works.

Colon motility is under circadian regulation

Colon motility follows a daily pattern. Typically, it’s higher in the morning and following meals. Additionally, coffee can also stimulate colon motility, as many of you are aware.

Outside of these conditions, colon motility is usually low. We don’t typically have to go #2 at 10pm unless we’ve just eaten. We also don’t wake up in the middle of the night to go. These aspects of colon motility indicate that it’s under circadian regulation.

Experimental evidence in mice confirms colon motility is circadian. And it turns out that cortisol is the primary circadian hormone that regulates colon motility. In mice, removing the adrenal glands caused loss of the circadian rhythm in the colon. Removing the pineal gland does not.

This makes sense. Colon motility is highest in the morning when cortisol is highest. Cortisol also drops as the day goes by, as does motility. Finally, there is a small bump in cortisol after each meal. This may be signaling meal consumption to the colon.

How to fix constipation: Cortisol and colon motility
Arrows indicate meal timings

So if you wanna know how to fix constipation, you have to start with your circadian rhythms.

How to fix constipation: Light exposure

The first step in getting your circadian rhythms right is to address light exposure. Getting adequate light exposure during the day and blocking improper light at night is a good start. This helps set the circadian rhythm of cortisol.

To be clear, we aren’t talking about getting artificial lighting during the day. Artificial light isn’t powerful enough to do the trick, you want sunlight. Ideally you go outside, and a commute in your car does the trick. If working at a desk, plant in front of a window.

If you live in an area with less light during the winter months, you can use a light to simulate the Sun. These devices should be in the middle of your visual field and put out at least 1000 lux of the proper wavelengths.

At night, you want to decrease your light exposure, particularly blue light. There are a number of ways to do this:

  • Wear blue blocking glasses
  • Avoid the use of lights high in blue light(LEDs, fluorescent lighting)
  • Use warm bulbs and lampshades
  • Purchase lights like Philips Hue or LIFX that mimic normal lighting conditions
  • Use f.lux or iris on your laptop
  • Utilize blue blocking technologies on devices that have them(Samsung TVs, Amazon tablets, etc.) Note: Iphone nightshift doesn’t work.

Addressing light exposure is the foundation of your circadian schedule. Light exposure essentially provides a reference point. Your organs don’t have watches, they contain biological clocks that require hormonal signals. These hormones help them tell time.

How to fix constipation: Feeding/fasting cycle

The next step in addressing circadian rhythms to fix constipation is the feeding/fasting cycle. The circadian clock in the colon is a peripheral clock, and the feeding/fasting cycle typically entrains the peripheral clocks.

A 1000 calorie meal stimulates colon motility. It’s important to point out that foods typically take ~24 hours to reach the colon. So consuming meals on a regular schedule promotes regularity by synchronizing colon motility.

In addition, time-restricted eating involves restricting your eating to a window of 12 hours or less. Though not studied, TRE may be a good way to sychronize the colonic clock to the master clock. Since colon motility is regulated by feeding and cortisol also plays a role, TRE may promote optimal colonic motility.

How to fix constipation: Diet and other factors

While circadian rhythms play a role in colonic motility, they’re not the only important factor. A person’s diet also plays an important role. A high fat diet reprograms the cortisol rhythm in mice. When you think of a high fat diet, think standard American junk food diet. Not low carb or keto.

Fiber is also useful for promoting colonic motility provided you have the microbiome for it. Fiber-fermenting bacteria in the colon create short chain fatty acids such as butyrate. Butyrate is the preferred fuel source for colonocytes, the cells in the colon. But if you don’t have the bacteria that do this, you won’t get the benefit.

A high proportion of hydrogen sulfide(H2S) producing bacteria is also problematic. When H2S is high, the colon prioritizes detoxification of H2S over the oxidation of butyrate for energy. This lack of energy inhibits motility.

Inflammation and exercise also play a role. Inflammation prevents colonocytes from absorbing butyrate. Thus, an inflamed colon cannot utilize butyrate for energy. Exercise, on the other hand, promotes butyrate uptake.

Exercise creates lactate which uses the same transporter as butyrate. It also increases fiber fermenting bacteria in the colon. A study in psychiatric patients found combined exercise significantly improved colon transit time.

Finally, exercise improves mitochondrial function throughout the body. This coupled with the above factors point to an important role of exercise in energy metabolism in the colon. Click here for a full review on the topic.


Constipation is caused by impairment of colonic motility. As such, correcting the underlying cause of impaired motility should correct the problem. Since the colon is under circadian regulation, addressing circadian rhythms should be your first step.

Optimizing your light exposure and time-restricted eating are the primary factors for addressing the circadian rhythm of the colon. Sticking to scheduled meals is also useful for promoting better motility in the colon.

Diet also plays a role. A standard American junk food diet negatively affects the cortisol rhythm. Since the circadian rhythm in the colon is regulated by cortisol, a low quality diet may impair colon motility.

Microbial factors play a role too. In order to get the benefits of fiber on motility, you need microbes that ferment it. By creating butyrate, these microbes can promote motility. But if you have high levels of hydrogen sulfide, this blocks the use of butyrate for energy. Thus, other dietary factors are also important.

Finally, exercise has many beneficial effects on the body. As a general rule, exercise increases mitochondria throughout the body. The mitochondria make more than 90% of energy in the body. They’re also where H2S is detoxified and butyrate is metabolized. Thus, more mitochondria means better colon function.

So if you want to know how to fix constipation, address the factors within this article. Start with circadian rhythms and improve the quality of your diet. But don’t stop there. Add exercise to build resilience in the colon and beyond.

4 thoughts on “How to fix constipation with circadian rhythms

  1. Anita Barnes says:

    I definitely have a problem with fiber and suspect a problem as you describe here. What can I do to help this? “Microbial factors play a role too. In order to get the benefits of fiber on motility, you need microbes that ferment it. By creating butyrate, these microbes can promote motility. But if you have high levels of hydrogen sulfide, this blocks the use of butyrate for energy. Thus, other dietary factors are also important.”

    • cincodm says:

      Hey Anita, that depends on each person’s individual situation. I am in the process of creating a program to help people address constipation and problems with fiber. Stay tuned!

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