I personally believe that exercise is overwhelmingly beneficial and exercise every day, but there is evidence that athletes have slightly increased risk of ALS (though this may be related to something other than exercise itself, eg maybe the fields on which sports teams play have harmful chemicals, higher head injury rates, etc)
Exercise creates a lot of oxidative stress, and after a while or too much exercise your body can’t handle the oxidative stress and that’s where things start going wrong.
It's common for people that do endurance sports to actually eat pretty low quality food in order to consume enough carbs. When I'm on bike trips I will pretty much eat just about anything including candy and things like maltodextrin in water just to keep myself going when I normally wouldn't eat these things. It's definitely not good for your gut. But overall is it better than being sedentary? Yes definitely
My father died of pancreatic cancer and both me and my sister-in-law who was a oncology nurse were frustrated with them, wanting to keep him eating those gross protein shakes that were filled with sugar.
[1] https://link.springer.com/article/10.1186/s12889-024-19545-z
My mom was diagnosed with terminal breast cancer 11 years ago, at 59. She wasn't super into fitness when I was growing up (no time with 4 kids to raise). But ~5 years after her diagnosis, still doing regular treatments and on loads of medication, she picked up running as a hobby.
She is absolutely incredible and I'm so proud of her. But she would be the first to tell you about all of the friends she made who died of cancer, including many much younger and fitter women, and I know this is obvious but I'll say it: it wasn't because they didn't exercise, it's because they didn't respond well to treatment. She had to stop going to her support groups because literally everyone she met there had died[1]. She is so fortunate that she's responded well, enough that she was afforded the time to emerge from the shock and depression and realize that she had a lot of life left. We are so lucky that she's here with us and well enough to develop new hobbies, etc.
I do think the sort of information in the study is interesting on a population scale. On an individual level the fact is that some people will respond to treatment and others won't. The ones who do may just feel well enough to start an exercise program. If they can, it may well improve the quality of their life, and may extend your time with them, and that's an amazing gift.
I'm not sure why I felt compelled to share my anecdote. Maybe just to share what the messy human side can look like.
[1] I should note that her support group was specifically for people with a terminal diagnosis. People in any other type of breast cancer support group won't have this experience.
WarmWash•1h ago