Halodrol has many of the properties you are looking for.... like increased red blood cell (RBC) production, improved endurance during exercise via better lactic acid clearing, enhanced oxygen and nutrient delivery to working muscles for greater endurance, better muscle glycogen restoration after exercise for faster recovery and; the inhibition of muscle destruction known as catabolism. But most PH/DS will have same edfects. Thus, they can be used for endurance athletes. A lot of people will answer this question from a bodybuilding/ power lifter perspective. This opinions will be biased. Fact of the matter is, AAS, PH, DS are all used by major athletes in everything from baseball, football to cycling, track and field events. I'm a believer that these compounds will react in your body based Halodrol also has many properties of traditional steroids like increased red blood cell (RBC) production, improved endurance during exercise via better lactic acid clearing, enhanced oxygen and nutrient delivery to working muscles for greater endurance, better muscle glycogen restoration after exercise for faster recovery and; the inhibition of muscle destruction known as catabolism. how you train. I played for a top ten collegiate football team from 2008-2010 and saw many people using both speed athletes (wide receivers, running backs) to power athletes ( lineman, linebackers etc) I was 250lbs running a 4.5 forty yard dash and bench pressing 450 and had a mile time of 5:32. No cramps, calf/back pumps etc. you can't take opinions from guys whose cardio workouts consist of them being out of breath after a brisk walk on a treadmill for 30min. For instance, I'm still at 250lbs, even stronger, lost a little speed due to no longer playing college ball (joined the military) currently running 30mg of DMZ and 30mg of M-Sten for 5 maybe 6 weeks. I'm in week 3 and my strength numbers are already up, size is up, BF is down and I just ran my fastest 1.5 mile ever post workout during my cardio session. Genetics plays a role, as well as different compounds react differently for diff people etc etc but how you train, and your overall cardiovascular endurance pre cycle + how you lift/ run on cycle will effect your results.