Should everyone exercise?

I don't get any real exercise for many years now and I am no where near fat. in fact, I am smaller/thinner than most guys, especially those around my age bracket as I am pushing 40 and I think I look largely similar to what I did many years ago. hell, I am not much bigger now than when I was at my peak energy to burn days as back in those days when I had about a 36" vertical jump, which was 16 years old, I was 5'7" @ 125-130lbs. now I am pushing 40 and I am 5'7" @ about 140-145lbs (on our scales I pretty much float in the 138-140lbs range for a while now but it might be a little low so I just claim 140-145lbs as that's got to be very close). although a while ago I was in the 150lbs-ish range for some years etc but have since lost some weight.

so while I am not visually much different from a while ago I can tell my legs (especially upper legs) have taken a decent hit as it does not take much before they are shot if I start doing a bit more heavy lifting (like they get that weak/shaky/wobbly feeling). but if the weight is kept down I am okay. I am still fairly quick though considering I don't get any real exercise for many years now as, at least as of roughly 3-4 years ago(as I have not tried lately), I estimate my top running speed to be about 14-15mph (plus, at that time I am pretty sure I weighed more than I do currently) as I know it had to be more than 13mph given the thing I was running against (a golf cart) should be right around 13.3mph given it does 1 mile in 4min30sec(maybe a little less), and it does it consistently(I tested a couple of different directions), which comes out to about 13.3mph and I can run faster than the golf cart in a quick sprint. but back in my prime, while I can't say for sure, I would guess somewhere around 18-20mph as I can tell I was noticeably faster back in those days (like when you ran you just felt more golden where as now I feel a bit sluggish when I run) and I had to be faster than most (at the very least) back in those days. because if I can do 14-15mph today(which is likely pretty close), and I am clearly more out of shape and weigh more today than back then, it's not a stretch for me to claim I did at least 18mph+ back in my prime, although I would guess about 18-20mph. because I could tell back in school I could comfortably top the easy majority and the ones I was aware of who could give me a run for my money (or beat me) tended to be a fair amount taller etc.

but anyways, to state the obvious... some exercise on a fairly regular basis is good for people as I don't think anyone would say otherwise as I am sure it's good for your heart etc. but people being people, they tend to avoid it. I think that's especially true when they don't have much free time because of a job etc it makes them that much more likely to avoid exercising and as we age we just don't have the energy we once did which makes it that much easier to slack off.