Fenix 5 and V02Max Readings-Confused

Former Member over 7 years ago

Hello all,

I run and bike regularly. I noticed though I will get a notification that my V02Max performance drops while running. I'll get maybe a -5 reading etc. I consider myself pretty fit I participate in duathlons and 10K's I don't know if this is a software issue or maybe I have the settings for the heart rate off because my heart rate Max is 168 I do exceed somewhat up to 170ish. Sometimes my pace per mile will change slightly I don't know if that will cause it to drop.

Any help will be appreciated.

Thank you

0 TrippyZ over 7 years ago

You get a vo2max reading of -5? Please link to an activity.

0 Former Member over 7 years ago

https://www8.garmin.com/manuals/webhelp/fenix5/EN-US/GUID-901ACCFC-FB0D-414E-B80C-54970AF4E357.html

Its a percentage deviation - I get that sort of reading if I am a little fatigued. Its probably a sign of just a temporary fitness issue

0 Former Member over 7 years ago

You get a vo2max reading of -5? Please link to an activity.

I think this is Performance Condition he's on about, seeing as he's mentioned -5 ??

0 mcalista over 7 years ago

I assume you are referring to Performance Condition. PC basically compares your current HR (as a percentage of max) with what someone with your VO2Max SHOULD be recording at your current pace. As such anything that causes your heart to beat faster (eg. poor sleep, overtraining, high ambient temperature) will show up as a negative PC number. Also, it would be normal for PC to begin positive, and then slowly drop as fatigue accumulates over a long run.

Also, as PC (and VO2Max) are very much based on your heart rate as a percentage of maximum, it is important that your maximum HR is recorded accurately. If you are seeing HR's of greater than 170, then your MaxHR is definitely NOT 168. The 220 minus age formula may be the population average, but it is rubbish at predicting the MaxHR of any one individual. Most people do not routinely exceed 96-98% of their maximum (as it hurts, and is not sustainable) - from this I would make a very rough guess that your true maximum is around mid to high 170's. If you are going to use VO2Max and PC to evaluate your training, I would strongly recommend doing a MaxHR Field Test to get a better fix on this number (you only need to do it one) - it will make your VO2Max estimate much more accurate.

0 Former Member over 7 years ago

I assume you are referring to Performance Condition. PC basically compares your current HR (as a percentage of max) with what someone with your VO2Max SHOULD be recording at your current pace. As such anything that causes your heart to beat faster (eg. poor sleep, overtraining, high ambient temperature) will show up as a negative PC number. Also, it would be normal for PC to begin positive, and then slowly drop as fatigue accumulates over a long run.

Also, as PC (and VO2Max) are very much based on your heart rate as a percentage of maximum, it is important that your maximum HR is recorded accurately. If you are seeing HR's of greater than 170, then your MaxHR is definitely NOT 168. The 220 minus age formula may be the population average, but it is rubbish at predicting the MaxHR of any one individual. Most people do not routinely exceed 96-98% of their maximum (as it hurts, and is not sustainable) - from this I would make a very rough guess that your true maximum is around mid to high 170's. If you are going to use VO2Max and PC to evaluate your training, I would strongly recommend doing a MaxHR Field Test to get a better fix on this number (you only need to do it one) - it will make your VO2Max estimate much more accurate.

That maks sense. Thank you very much. I will do as you suggest.