Altitude Acclimation 2

Oxygen we inhale is transferred to our blood using gas exchange at our capillary beds. Capillaries are the smallest blood vessels in the body, at only one cell thick, and when they form a network (or capillary beds) between our arterioles an venules, both slightly larger blood vessels in our circulatory system, they are the site where O2, CO2, and other nutrients are exchanged between the lungs and the blood. Oxygen-poor blood is pumped from the heart toward our lungs. Once there at our capillary beds, O2 moves from our alveoli, or the sacs in our lungs, to the blood and CO2 is offloaded. The O2-rich blood is then pumped back to our heart and then to the rest of our body. Image from

By on July 16, 2018 | Comments

Bryon Powell

Bryon Powell is the Founding Editor of iRunFar. He’s been writing about trail running, ultrarunning, and running gear for more than 15 years. Aside from iRunFar, he’s authored the books Relentless Forward Progress: A Guide to Running Ultramarathons and Where the Road Ends: A Guide to Trail Running, been a contributing editor at Trail Runner magazine, written for publications including Outside, Sierra, and Running Times, and coached ultrarunners of all abilities. Based in Silverton, Colorado, Bryon is an avid trail runner and ultrarunner who competes in events from the Hardrock 100 Mile just out his front door to races long and short around the world, that is, when he’s not fly fishing or tending to his garden.