Yeppers. It triggers the brain to feel the big happy. Usually I'm not too happy when I try to start moving or when I'm just moving. But once I'm running I'll usually have some point between 0-3km where it starts feeling good. And from there on out it keeps feeling good even if I'm tired.
I'm with you. Spent my life playing sports growing up, mainly swimming. Went into the Marines after. Constantly was in very good shape. I hate working out. I'm mid-30s now and I'll walk for an hour at 4+mph, I'll ride my bike, and those are fine because I'm out and about, but I'm just so over gyms and running. I think it's for the best too, running is not great on your knees, and it also just sucks. I used to run a ton, but the only reason I did was because I didn't want to get put in a situation in the Marines where I couldn't do something. So I just ran. Never got the runners high or anything.
Not everyone is built the same. I loved exercise as a kid, and as I got older my sleep apnoea stopped me enjoying it. You know that good feeling you get after doing exercise, how your body feels energised and powerful? For a long time, I wouldn't get that, because instead of recovering through sleep, my body was suffocating itself all night and I'd wake up feeling like I'd been beaten up underwater.
I tried and tried, but until I got a diagnosis and therapy, there was no use. I couldn't enjoy it, I just got a headache and muscle cramps and spent the next day or two laid out. You can't get healthier through exercise if your body won't repair the damage the exercise is doing.
Even now, if I have a bad night, exercise is off the table. In fact, I get anhedonia, which is the pathological inability to derive pleasure from anything.
And yeah, I am way more likely to die of a heart attack, but that's not a lifestyle choice. It's just my condition. I was denied life insurance over it.
So maybe next time ask questions before you make judgements.