That's a vast exaggeration. At Denver's altitude, 1608m, there's about 85% as much atmosphere as at sea level. To get down to 50% atmosphere, you'd need to clim

That's a vast exaggeration. At Denver's altitude, 1608m, there's about 85% as much atmosphere as at sea level. To get down to 50% atmosphere, you'd need to climb to around 5500m which is higher than Mount Elbert.