VO2 max declines by approximately 10% per decade after age 30-40, and maintaining or increasing it requires moderate to vigorous intensity exercise.

“your average for your age but I'm afraid that's not good enough because your VO2 max is also going to decline so we're going to have to go ahead and cross that hike off your list”

“produce a VO2 max above 30 milliliters per minute per kilogram and if you can do that that that basically buys you a whole bunch of activities that means you could walk up a six percent grade at three miles an hour you know for a period of time not necessarily for an hour but but perhaps for if you know 20 15 minutes”

“if a 30-year-old's VO2 max Falls below 30 there's a huge problem”

“for sure and after about age 30 to 40 into your 50s your v2 max starts to decline about 10% per decade so if you're not doing something to maintain that yes you can build it up as much as you can into your 30s and 40s, but if you aren't engaging in moderate to vigorous intensity exercises at age 40, 50, 60, 70, your V2 max is just going to continue to drop 10% per decade”