Confused on vo2 work

Got a bit lost on vo2max work. Want to understand whether I need to change anything to get the right benefits.

Started with snowfire 4x 5 min 106 percent. After 2.5 min I reach 90% max hr. Thereafter hr increases to 94% max hr.

Now after some weeks being able to finish septeret 4x 5 min 115 percent. I have difficulties reaching 90% Max hr. Say after 2.5m I reach 88% en couple of sec before end of interval I reach 90% or slighly below.

Power went up - hr went down. I am focusing on sustained build and see improvement. Should I nevertheless consider workouts pushing my hr up more?

You had a rest period recently? Low HR is often a response to fatigue.

Alternatively lower HR is also an adaptation to the vo2 work.
if at the same power, more blood and stroke volume would net the lower heart rate.


Yep - would be useful to know RPE and respiration rate to do a bit of triangulation.

In an ideal world you are getting fitter @Grutte (more power at lower HR) but you could also be coming down with something or overtraining. How do you feel the effort went, hopefully for power you perceived it was easier (comparatively at least) which is a sign of that ideal :wink:

Experienced this myself in my most recent VO2Max block - general consensus was carrying fatigue as the block progressed was limiting ability to raise HR.

Depending on school of thought you are following, whilst striving for >90%MaxHR is great, working at 88% is still going to provide some adaptation one would hope and if you are hitting power targets then I would consider the VO2 work to be successful in the round.

This thread may be of particular interest and I also link my post where I raised a similar query

Thanks all. Think it was a combination of fatique and alcohol the day before. I did the vo2max intervals a day after longer hard outside ride.

I just finished first similar (4x 5min) vo2 max training now after recovery week - and without outside ride the day before - and now I reach 80% max hr after 90 sec and hr keeps going up to 95% of max hr.

1 Like