Doctor explains why colon cancer is rising in adults in their 30s—and why a 45-minute gym session isn't enough

Colon cancer cases are increasing among younger adults, and prolonged sitting may be one of the overlooked reasons behind the trend, according to Dr. Priyam Bordoloi. In a post on X, the doctor highlighted that while genetics often gets the blame, medical evidence increasingly points to a common modern habit—spending most of the day sitting—as a significant independent risk factor. He also stressed that a 45-minute gym workout cannot fully offset the health effects of sitting for long hours.

What is causing the rise in colon cancer among younger adults?

In his post, Dr. Bordoloi posed a multiple-choice question asking what the "actual culprit" behind the increasing cases of colon cancer in adults in their 30s could be:

• Eating spicy food
• Sitting most of the day
• Sleeping less than five hours
• Daily coffee

According to the doctor, prolonged sitting is the correct answer.


He noted that many people find it hard to believe that an everyday activity such as sitting could contribute to cancer risk. However, he said growing medical evidence suggests that extended sedentary behavior has emerged as a strong, independent risk factor for colon cancer, particularly among adults in their 30s and 40s.

How prolonged sitting affects colon health

Dr. Bordoloi explained that spending around 10 hours a day seated at a desk or in front of a screen slows down gut motility—the movement of food and waste through the digestive system.

When gut motility decreases, waste remains in the colon for longer periods. According to the doctor, this means natural toxins in the waste stay in contact with the colon lining for an extended time, potentially causing continuous irritation to the cells.



He also said prolonged inactivity can disrupt metabolism by increasing insulin levels and promoting chronic, low-grade inflammation. Although these changes are not immediately noticeable, they may create biological conditions that allow abnormal cells to grow and multiply more easily.

Why a 45-minute gym workout may not be enough

Many people believe that exercising after work can cancel out the effects of sitting all day. Dr. Bordoloi disagrees.

"The most heartbreaking part is that people think a 45-minute gym session after work erases this. It doesn't. You cannot out-train 12 straight hours of sitting," he wrote.

According to the doctor, the human body is not designed to remain seated for most of the day, and regular exercise alone cannot completely compensate for prolonged sedentary behavior.

What can you do to reduce the risk?

Dr. Bordoloi said people do not need to quit desk jobs but should make an effort to interrupt long periods of sitting.

He recommended simple habits such as:

• Standing up regularly during the workday
• Walking while taking phone calls
• Stretching for two minutes every one to two hours
• Avoiding sitting continuously for long periods

According to the doctor, frequent movement helps keep the digestive system active and may reduce the harmful effects associated with prolonged sitting.


Disclaimer: This article is for informational purposes only and is not a substitute for medical advice. Consult a healthcare professional for diagnosis, screening, or treatment.