I'm 60+, spent most of my time outdoors (a few million+ SLOC of exploration geophysics sensing | analysis | GIS code written in field ) and have yet to meet a bodybuilder that can put in an 8 hour shift on a long handle shovel day in day out.
Wirey station hands can, skinny and|or fat farmers can, I still can and my father (still alive, born 1935) still can.
Sustained steady physical work is a thing that seems largely orthoganal to gym fit.
A lot of this is because being overly string is a disadvantage. Body builders can lift more weight, but that's a lot of extra muscle to move when lifting relatively light things hundreds or thousands of times. A body builder could literally be working twice as hard as a wiry person, by having to lift their own muscles.
The physiological property that is used as a proxy for cardiovascular fitness is usually the bodys maximum oxygen consumption.
Strength training apparently has only very very little effect on that. [1] [2] [3]
Generally, to increase the maximum oxygen consumption, one has to exercise at about 90% of the maximum heart rate. This usually doesn't happen during strength training.
From what I gather, you achieve a base level of VO2max with strength training that is better than sedentary people but worse than people who do regular cardio. So if your VO2max is initially low, strength training does have a significant effect on it. But if you want to increase it yet more, you have to do cardio (which you can do with weightlifting too btw!).
