Sleep, Naps and Colorectal Cancer

Medically Reviewed by Guglielmo Niccolò Piozzi, MD
Written by Samantha PhuaMar 18, 20244 min read
Man Sleeping

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With numerous risk factors contributing to its development, colorectal cancer is, without a doubt, a significant public health concern. Given that it is a significant cause of cancer-related morbidity and mortality worldwide, understanding its risk factors is crucial for prevention and early detection.

While factors like diet, genetics and lifestyle have been extensively studied, recent research delves into the potential link between sleep patterns and colorectal cancer risk. You might wonder, how does sleep relate with your gut health and, ultimately, colorectal cancer risk?

In this article, we take a closer look at the findings of one particular study that focuses on the relationship between sleep patterns and colorectal cancer. While these findings may shed light on how important maintaining a healthy sleep routine is in not only boosting your overall health, but also lowering your colorectal cancer risk, there is no concrete evidence to suggest that an irregular sleep schedule will exacerbate cancer risk.

What’s the link between sleep and colorectal cancer?

Sleep duration has so far been linked with higher risk of cardiovascular diseases, type 2 diabetes and obesity. Given that type 2 diabetes and obesity are both also known colorectal cancer risk factors, it thus becomes no coincidence that sleeping too much or too little can increase your cancer risk.

Overweight Man on Scale

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In a study led by Kyriaki Papantoniou and published in Scientific Reports, the team observed the relationship between sleep patterns and colorectal cancer incidence. Patients with colorectal cancer were compared with a control group, and other factors such as sleep duration, daytime napping and night shift work history were also considered.

Based on their findings, the short story is that we should stick to a regular sleep schedule of 7 to 8 hours while following the circadian rhythm to minimize our colorectal cancer risk. The longer story, meanwhile, is a lot more nuanced.

How long you sleep matters

The connections between sleep duration and colorectal cancer are nothing short of intriguing. Specifically, sleeping 8 hours or more was associated with an increased colorectal cancer risk. One might assume that since sleep is also linked with higher obesity risk, this would apply to those who fall into the overweight/obese BMI range. However, the association was more pronounced among individuals with normal BMI, suggesting that other factors besides obesity may play a role in the higher colorectal cancer risk.

The link between sleep and colorectal cancer is less pronounced when judged based on short sleep durations. While sleeping 5 hours or less did not have any statistically significant association with colorectal cancer, it hinted at an increased risk for gastric cancer, particularly in males. While this is inconclusive, it warrants further investigation into the impact of short sleep times on gastrointestinal cancers.

When you sleep matters too

If you typically enjoy an afternoon nap, you may be at higher risk of colorectal cancer. While the mechanisms of how naps relate to cancer still require further study, sleeping more than 30 minutes in the day has been linked with higher colorectal cancer (and gastric cancer) incidence.

Your colorectal cancer risk is further increased if your penchant for afternoon naps comes as a result of frequently working the graveyard shift. The study also explored the interaction between sleep patterns and night shift work. Short sleep and daytime napping had a stronger impact on colorectal cancer risk among individuals with a history of night shift work. This suggests a potential joint effect of sleep disruption and circadian rhythms on gastrointestinal cancer risk.

Man Working Late at Night

Source: Shutterstock.

Is sleeping according to the circadian rhythm sufficient?

The findings so far suggest that circadian disruption is generally associated with higher colorectal cancer risk. However, much research is still required to draw more conclusive connections between sleep duration, circadian rhythm and colorectal cancer, in particular pertaining to the mechanisms that lead to increased risk.

In addition, while the findings reinforce pre-existing notions that link sleep, obesity and colorectal cancer, the impact of sleep on individuals in the normal weight range suggest that there are other mechanisms also at play.

Will sleeping according to a regular sleep schedule eliminate your colorectal cancer risk? While catching your 7 to 8 hours every night potentially helps reduce your likelihood of developing the disease, remember that there are still other risk factors in the form of genetics, medical and family history and other lifestyle and dietary habits that could exacerbate your risk.

We cannot, with hundred percent certainty, lower our colorectal cancer risk. However, we can manage our risk by consulting with medical professionals on our innate risk and getting screened at the right intervals. Colorectal cancer that is detected at an early stage is highly treatable, and so don’t be discouraged and take heart that your medical team will work out the best treatments for you.

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This article has been medically reviewed and fact-checked to ensure our content is informed by the latest research in cancer, global and nationwide guidelines and clinical practice.

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