I believe I have lost fitness doing LSD running. Its made me slow like a slug. If you have never exercised & need to lose fat and ease your heart into training then it has value.
But I am an ex infantry soldier, I have lifted weights 26 years. Thanks to LSD my cardio level is very poor.
The fix ? Kettlebell snatches and the viking warrior workout will save my ass. I expect that only 1-2 months doing the cardio KB snatch routine will have my cardio in pristine condition. No more long slow runs to the beach for me.
Kettelbells are far more effective for improving cardio and fat loss while maintaining and increasing muscle.