Personally, I prefer lower intensity exercise that can be sustained for longer periods. I believe there’s less likelihood of injury, more calories are burned, and the gains are more transferable to real life. When I do yard work or something, it’s not just one quick burst and then I’m done; I need to sustain the activity for at least 30-60 minutes. I want to build long-term work capacity, not just explosive power.
I also feel like I get more out of an easy 4-mile jog than a fast mile. There’s a place for speed work and intervals, but my regular work-outs tend towards the long/slow for running and to higher volume for weights.
I used to do 20-minute work outs with high weights but low total volume. I got stronger, but my conditioning was horrible. I didn’t see my best health gains until I could work out for longer periods of times. I think building total work capacity is one of the keys to beating chronic fatigue.