For the past 10 days I’ve been training at Boulder, which is about 1,600 meters above sea level (some days we reached 3,700 meters!). Doing most of my training at sea level, I knew this was going to be a challenge. I kept measuring my HRV during this time as I love seeing how changes in the environment affect my HRV. Of course, there are other factors to take into consideration when looking at the HRV trends besides altitude: travel, sleep (I was sleeping on a couch!), traini