VO2 Max drop after change to Max HR setting

badbri said:

I've done a few max HR tests but it's mostly an unnecessary risk.

I tried to push myself once to achieve a peak Vo2max of 58.

Looking back, I won't be pushing hard again to face unnecessary risk.

So I am sorry if it sounds insulting to some of the guys here but I am just advising on the safe side. There could be some amateur runners around.

My only concern doing max-effort run tests is how sore I'll be for the next 5 days! 

I understand the concern for new "old" runners.  I just completed my 25th marathon last month, and plan to keep running them for as long as I am able. 

I had a very similar thing happen.  I started running on my own at age 62 recently.  About 8 weeks ago, I switched to the Garmin 10K coaching plan and my VO2 Max per my Forerunner has been steadily dropping, although I'm now up to 8 miles.   Max heartrate was calculated based on measured resting heartrate and reserve.  With the longer distances, my pace is slower than it was prior to the coaching plan, so my thought is the perhaps it's an issue of lower intensity resulting in lower VO2 Max.

I had a very similar thing happen.  I started running on my own at age 62 recently.  About 8 weeks ago, I switched to the Garmin 10K coaching plan and my VO2 Max per my Forerunner has been steadily dropping, although I'm now up to 8 miles.   Max heartrate was calculated based on measured resting heartrate and reserve.  With the longer distances, my pace is slower than it was prior to the coaching plan, so my thought is the perhaps it's an issue of lower intensity resulting in lower VO2 Max.

If you started doing new kinds of exercises (increasing the distance in this case), it's normal for your VO2max to drop temporarily until your body adapts. To my understanding, people don't have a single VO2max figure that would apply to everything. Different kinds of sports use different muscles in different ways, resulting in different VO2max figures. That's why many Garmin watches have a separate VO2ma for running and cycling, for example. But even for just running, different kinds of runs use muscles differently. Muscles tire out and utilize oxygen less efficiently later in long runs, for example, until they strengthen and develop enough to handle longer runs better. (You can see this easily from the Performance condition graph of your activity in Garmin Connect.)

I had the same experience as you when I started varying my runs by joining a Garmin Coach program. Initially my VO2max dropped on long runs, and then returned to the same level as before when I got more comfortable with running longer (and now it's slowly getting even better).