If it's working it's probably just a right amount for them, not too much. This is the one thing that people are missleading themselves on - if somethings works it's probably right for that person no metter how hard or easy it is. For example there are no such a thing as big dosages - it's just for whom, as 2g for 150lbs its too much probably, but for 250lbs it may be too little. So for the oxygen gusys it's probably not too much, it's just suit for them becouse they are basicaly have the best health care in the world, eat, sleep, and recover perfectly, have no stresses etc. It probably not gonna works for someone who has 3 kids, shift job and a wife that are driving him crazy xD - but that's the difference, there are no other rulez in bodybuilding then your OWN body feedback - the amount of work we need is mostly dependend on how well you can recover, as well as how much gear or food you can or need intake - its all relevant to the person needs. Abviosly i know that you know that, i just wanna to pinpoint that for those who don't as there are still topics like "how many sets should i do per week" etc. And that question is just impossible to answer different then - try and you find out yourself.