I would add in GW I almost made a stand alone thread today about my experience with it on day #19
The endurance is off the hook, I can do 45 mins on the treadmill @4.2MPH incline 5% where before I was doing 25 mins @3.2mph and 3% incline!!
I could stay in there and keep going...LOL I know there is NO WAY this is placebo!
I'm also a rock drummer on the side, my drum solo would be 2 mins and I thought I was having a heart attack, now I can go a solid 5 mins and walk off and have my breath back in 45 seconds to a minute....