Knee implants, significant negative hormonal changes for men over 50 miles/wk. Repetitive stress injuries are no joke.
OP is probably not aware that the Olympics does not have ultra-marathon type events which are generally very unhealthy for participants, only a 10K and a marathon (and shorter sprints of course)
WRT knee damage, I found a Harvard report saying that running helps protect your knees against arthritis [0]. You'll have to source your own hormonal claim because it was too vague for me to find much, but what I did find did not seem negative [1][2].
That first link is just a Q/A. There is no study or report linked.
Almost all studies use untrained vs trained athletes. They rarely qualified what "trained" means and could be anything from a lifetime athlete to someone who self-reported following a 6 week plan prior to the study and now we consider this person "trained". Most athletic studies are used to compare a sedentary person to someone who workouts casually (less than about 10 hours per week). Once you pass this point, you're in diminishing returns territory and you've got to actively sacrifice some parts of your overall health to make gains in a single activity (sprinting, jumping, etc.).
So will running a few times a week help fight mild arthritis? Probably. Will training like an Olympic athlete? No. Same thing applies to the OP article. Will sledding down a hill give you brain damage? No. Will constantly sledding at Olympic athlete speeds and g-forces? Seems like it.
Yeah, you definitely have to sacrifice parts of your overall health if you want to exercise more than 90 minutes per day.
/s
Diminishing returns doesn't mean that you have to sacrifice anything (besides some idealized notion of efficiency). The hurt-your-overall-health point is somewhere much closer to Olympic athlete than it is to 10hrs/week. If you just vary the activities a little, you will have no trouble with spending a lot more time on exercise. People who literally do only the one physical activity they compete in are straw men.
PS: The number of people completely clueless about fitness on HN would be hilarious if it weren't so sad.
Working out (not including warmup/cooldown) for 90 min, 7 days per week is insane and you will be less healthy. No rest day means you'll be over trained in less than two weeks, and your workouts will get worse over time. Not only that you'll probably get injured within a month.
Let's say you create a sane schedule of 3 days on, 1 day off (or similar) and you workout 2 hours per day (20 hours in 2 weeks) and let's assume you're sleeping the necessary 10 hours per day for this training schedule. And we'll make the very generous assumption you manage to not get injured for an extended period of time. You're still at higher risk of infections due to suppressed immune system[1] and also at a certain FFMI, your cardiovascular health actually starts to decrease[2]. Plus the chances that your nutrition, mobility, sleep schedule, and training plan are all good enough to not get you injured or sick during training, are astronomically low.
I only workout 60-75 minutes 5 days/week and I'm already at or above the FFMI level where my heart health is worse than if I just stuck to moderate intensity exercise for less time.
Huh, seems I read "workout" as "generic exercise" in your previous post, but I guess you meant high intensity stuff exclusively. I'm pretty sure most athletes have stuff to do that doesn't really have this sort of limit -- like cardio or technical work.
The thinking behind my post was that if you add up training (for the activity they compete in) and all the other physical activities people do, the differences in training volume will be dominated by the other differences -- consider people with jobs that involve manual labor, or, to a lesser extent, bike commuters. Perhaps this was controlled for in the studies?
The other thing I had in mind was people whose sports involve lots of different movements one can practice -- say, ice hockey. I have no idea whether ice hockey shooting practice counts as high intensity... but it's not nothing, and doesn't seem much like ultra running either.
Source? I would expect these are much more common in obese people than in habitual runners. My understanding is that runners have been found to have healthy knees, e.g. with a bit of googling I find [1][2] (but haven't read them).
> significant negative hormonal changes for men over 50 miles/wk
They have found somewhat lower testosterone levels, but I don't know of any study finding negative health impacts. Do you have a source for "significant negative"?
OP is probably not aware that the Olympics does not have ultra-marathon type events which are generally very unhealthy for participants, only a 10K and a marathon (and shorter sprints of course)