The absolute first thing you should think with articles like this: is the journalist confusing correlation and causation??? And sure enough, the main finding a

The absolute first thing you should think with articles like this: is the journalist confusing correlation and causation??? And sure enough, the main finding according the scientific paper [1] In this cohort of 177 709 men followed up for a mean of 9.6 years, higher cardiorespiratory fitness was associated with a lower risk of colon cancer incidence. A lower risk of death from lung and prostate cancer was also noted. Keyword being associated. So one needs to wonder, could the causation run the other way? Perhaps, people with cancer are apt to exercise less. In fact you only need to exercise a little bit less to get to a level of 3% less fitness. Seems an entirely reasonable explanation. If so, this means that exercising more would not reduce the chance of getting cancer. Since cancer is a bit of a dice gamble, that does not seem impossible to me. Yet a further alternative, maybe exercise and lower cancer risk are both caused by something else. Some adjustments were made for various factors, but maybe if you are well-off, you tend to live better, leading to higher fitness and to lower cancer. So, good to know, but the Guardian article reads way to much in this. [1]: https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2806585%20 https://jamanetwork.com/journals/jamanetworkopen/fullarticle...