★★★★★
Sufficient levels of vitamin E, natural E and not synthetic will oxygenate the blood. Start with 200 iu daily and increase to 400. I've been on 800 for thirty years. I've been twice in last ten years to the Rockies... Above 11,000 feet camping. No headaches etc. When hiking, yes I had shortness of breath but that is expected. No chest pain, headaches... To test myself I even ran for a few minutes at the continental divide... Still no headaches. Did that when I was sixty years old.