If all you care about is the day you die then that is one way to see that data. Regular excercise will improve significant aspects of your life before that date though. If I didn't get measurable daily benefits from being fit I would probably still do it, since some activities are fun anyway. Mountain biking, climbing, swimming, all pretty fun.
Yeah, I was glad to stumble on swimming. I’ve always tried to jog a bit, but I’ve always hated it (and still do). I’d never really properly tried lap swimming (we did it a little in primary school, apart from that I’d only done recreational swimming), but I took to swimming laps very quickly and easily, now I really look forward to hitting the pool for an hour, two or three times a week.
There is a bit of a curve to get over with technique, breathing, etc. where you really can’t swim very far and you feel super slow at the start, but if you work on it it you can build up pretty quickly. You burn far more kilojoules in the pool than doing something like running too which is nice! I’m 32 now, been doing the swimming for three years now, and with a bit of diet improvement I’m definitely in the best shape I’ve been in since high school.
I’d definitely recommend it for people who don’t like the feeling of other aerobic exercise like running or cycling.
How do you get over that initial hump with breathing? I tried for months (maybe a whole year? But anything over 5 laps and I'd get a headache. I even bought this guy's videos: https://youtu.be/R4QQ_YXCMok
For $100 and paid a lifetime fitness swim instructor $180 to help me improve, but to no avail. (The videos helped some, the instructor was garbage).
It mostly just came with practice but perhaps I already had some advantage because I've done a lot of singing and also played wind instruments (trumpet mainly) for many years. Getting headaches doesn't sound great though - perhaps you were pushing too hard? You want to push through discomfort (and there is a lot of that especially at the start) but not into pain. Maybe just start with four or five laps at a slow pace and then try to add another lap every two weeks or so?
In terms of videos I quite like this channel on YouTube - https://www.youtube.com/@SkillsNT - it's all free content (they make some money with paid intensive camps every now and then at various places around the world but obviously you don't need to do that!). They have a fair bit of stuff about breathing, including exercises to do both in and out of the pool to improve breathing and how your body responds to CO2 in the bloodstream. Those exercises could also potentially help.