I'm a national level competitive bodybuilder. As part of my training routine, I do 1/2 hour of level 12 interval training on the stairs a minimum of once a day (i.e., just like running bleachers at full tilt) Some days, I do three workouts: intervals in the morning; weights midday; intervals at night, and, sometimes, I walk, too.
I can hold my heart rate at over 160BPM for over 20 minutes.
I'm not only strong, but, I also am very lean, and I have exceptional endurance. I'm considered at 0 risk of heart attack by my doctor.
I would argue that, in terms of overall athleticism, I have a higher level of all indicators across the board. I assure you, I'm quite fit by whatever measure you use.
Yes, there are fat folks that lift weights; skinny people that run and have no muscle mass.
In my case, sports science is leveraged to the highest degree to maintain an optimal machine through advanced training techniques, and various forms of manipulation of the body.
You can't do bodybuilding at the level I do without a comprehensive understanding of how the machine works.