Risks of Prolonged Sitting for Cancer Survivors

I have written many times about the importance of exercise, and I suspect you may be as bored by the topic as I am. However, sometimes a study is published that again demands our attention and consideration. An example from JAMA Oncology explored the association between daily hours of sitting and lack of exercise and survival. The results are important and reinforce what we already know.

We have to find ways to motivate ourselves to move.

The overall finding was that cancer survivors with prolonged daily sitting (defined as being eight or more hours per day) had a fivefold increase in the risk of death from cancer or other causes as comparted to those who were active. Fivefold is a lot!

This prospective study followed 1,500 survivors for up to nine years after their diagnoses. More than half reported absolutely zero exercise activity per week while only 27.6% met the recommended target of 150 minutes or more of weekly physical activity. One-fourth of the group reported sitting for more than eight hours each day while another one-third reported 6-8 hours of sedentary behavior. As I type this, I recognize that many of us have desk jobs that require those hours of sitting, but there can be ways to mitigate that reality.

Let’s look more closely at the people in this study. Their average age was 65 and slightly more than half were women. Most were white, and the most common cancers experienced were prostate, breast, melanoma, cervical, and uterine. Almost one-fifth also had diabetes and one-fifth had cardiovascular disease. More than two-thirds were classified as being overweight or obese.

We know that being diagnosed and treated for cancer is a life-changing and sometimes lifestyle-changing experience. We usually finish months of treatment exhausted and in less strong physical condition than we were before diagnosis. In spite of the many recommendations to continue with mild to moderate exercise during and after treatment, clearly many of us do not do so. This often corresponds with aging and the common diminishment of activity that can accompany our older years. The study participants fit this profile and many were already contending with other medical issues.

What is unique about this study is its dual focus on both activity and sedentary time. There have been many studies looking at exercise, but most have ignored what happened in all the other hours in a day. As an example, a meta-analysis published in 2020 reported a 22% increased risk of death and a 53% increased risk of death from cancer for people who had been treated for colorectal cancers and held a high level of postdiagnosis sedentary behavior. I find these numbers alarmingly high.

What can we do about these risks? The clear answer is that we have to find ways to motivate ourselves to move. There are many suggestions of how to do this, and the two most common recommendations are to find exercise that you enjoy and to make it a habit. We don’t have to become athletes, but we do need to move our bodies. Remember the old adage: use it or lose it. Apparently, in this case, losing it might be a major and permanent loss.