If you knew that exercise reduces cancer risk, would you not follow it? In recent times, there have been link-ups between physical activities like exercise and reduction of cancer risk.

A confirmed relationship has been seen between exercise and reduced cancer risk. This relationship is a ray of sunshine for survivors of cancer treatment, for they can easily prevent a recurrence by adopting a healthy lifestyle after rigorous treatment therapies. With so much emphasis on such a link-up, here is everything you need to know about exercise and cancer risk.

Does Regular Exercise Reduce Cancer Risk?

Yes, regular exercise reduces cancer risk greatly. In the past, despite several studies into the relationship between physical activity like regular exercise and reduced cancer risk was inconclusive. However, recent research and meta-studies seem promising.

A recent study by Danish researchers, conducted with mice, suggests the activation of specific immune system defenders called natural killer cells due to moderate levels of exercise. In the study, a group of mice was implanted with melanoma cells and divided into two groups, one in a cage with a running wheel and the other in a regular cage. After four weeks, fewer mice with a moving wheel have developed cancer compared to sedentary ones. Further analysis brought to light the presence of an increased amount of natural killer cells in mice that used the wheel, a possible effect of adrenaline.

In a study conducted by the National Institute of Cancer, the USA, published in the JAMA Internal Medicine in May 2016, supports the theory of reduction of cancer risk due to regular exercise and physical activity. 12 extensive studies across the USA and Europe were meticulously conducted by the research team covering over 1.4 million people who had provided their lifestyle details and medical history. After comparing cancer rates among the study pool, the team found a possible relationship between regular exercise and physical activity and reduced cancer risk. They found that individuals with the highest level of physical activity have lower rates of different types of cancer including, breast, colon, kidney, oesophagus, head and neck, rectum, bladder, and blood cancers.

Despite these studies and others, nothing can be conclusively said about exercise reducing cancer risk. However, the probability is quite high at this point.

How does exercise reduce cancer risk?

Recent research and studies have presented data on how exercise reduces cancer risk. Regular exercise can reduce cancer risk of up to 13 types. The exact mechanism by which exercise and physical activity reduce cancer risk is unknown.

However, doctors and researchers have identified three possible ways in which exercise reduces cancer risk:

Lower insulin levels:

Insulin is well-known for its role in blood sugar metabolism due to the increased number of diabetes cases in the world. However, it has a lesser-known function of preventing cell death by inhibiting activities that lead to it, known as 'anti-apoptotic' activity. This function of insulin can promote cell proliferation which can lead to malignant cell growth in individuals. Such a risk is prominent in breast and colon cancers. Regular exercise and physical activity, like aerobics or resistance training, maintain insulin levels, thereby reducing the risk of overt cell growth.

Fat management:

Individuals with high levels of fat in their bodies have a higher risk of cancer, according to several studies. One of the reasons for this is the chronic low-level inflammation in obese people that causes DNA damage, increasing cancer risks. Moreover, with high levels of insulin and growth hormones, people with increased fat levels have a higher risk of contracting certain types of cancer like endometrial, breast, prostate, kidney, colon, and gallbladder cancers. Regular exercise and physical activity help individuals maintain fat levels in their bodies, thereby reducing the risk of cancer and other lifestyle diseases.

Lower sex hormone levels:

Studies have shown that increased exposure to sex hormones, i.e., estrogen in women, increases the risk of Breast Cancer. A meta-analysis of 38 cohort studies concluded that women who were moderately physically active had 12-21% lower risk of Breast Cancer than the ones with no or low physical activity. The reason behind the reduced risk is the low levels of sex hormones in physically active individuals.

Exercise to reduce cancer risk: Recommended Level

Based on the available data, experts recommend, the following exercise to reduce cancer risk and other chronic diseases:

• 150 to 300 minutes of moderate-intensity aerobic exercises or 75-100 minutes of vigorous aerobic activity per week.
• Muscle-strengthening exercise at least 2 days in a week
• Balance training

Does exercise reduce cancer recurrence?

After most cancer treatments, survivors have a hard time coping with a weakened body and mind. Physical activities like exercise reduce cancer risk; it also help during and after treatment to maintain a sense of control and supplement their treatment. However, when it comes to exercise, and reducing the risk of cancer recurrence, more conclusive and binding studies are needed.

So far, with the limited number of studies, regular exercise has been shown to decrease cancer recurrence and death risk in survivors of three types of cancer: breast, colorectal, and prostate. Studies have shown that survivors who exercise regularly have a 40-50% lower risk of recurrence of Breast Cancer and a 30% and 33% lower risk of death from colorectal and prostate cancer, respectively.

Currently, there are no prevention methods for cancer. However, these studies on the relationship between exercise and reduced cancer risk seem promising for a future where disease can be prevented.