tangerine tango2
3700 feet is "altitude" but it's miniscule. I've raced in spearfish, SD. We did not alter our race plans on account of altitude, we paced just like we would at literal sea level. And while running it felt like sea level.
The plot of altitude versus performance decline is not linear. For example, in the mile if you get a 2.5 second performance decrease at 4500 feet, double that to 9000 feet and the performance decline will be more than 5 seconds.