Try running up while this guy gives you motivation he always has & always will. When we got to the Top. True spiritual awakening Tough Spotters research studies have explored the idea of taking advantage of the body’s physiological changes at high altitude as a “natural blood doping” effect. As the blood increases its red cell volume in response to a lower availability of oxygen, VO2 max also increases. Sea level performance has been shown to improve as a result Happy Days Happiness Tough Spotters World wide