I use 100% beet juice not the powder although I am told the powder works too. I was prescribed a beta blocker by my MD. It damn near killed me. It basically acts like a car governor on your heart. You just can't make any efforts. You can imagine what it was like trying to do a 50 mi. club ride. And, I got really depressed. A fellow cyclist is a Naturopathic Doctor. She advised beet juice and it worked.