Did my usual 2 x 20min threshold session with 5 x 30sec uphill sprints. Finished session ok, but all the way through my heart rate was low, although breathing was normal for a threshold plus session with the usual leg burn, but still couldn’t get heart rate up. Didn’t feel tired during session, but couldn’t feel my heart pounding like it normally does. Now I don’t feel like I’ve not anything. Any ideas why?

Maybe you are run down? It is winter etc. Or the hrm is inaccurate?

Could be faulty hrm, but normally you can feel your heart pounding during and at the end of each effort. May be a little run down, but feel fine. Cheers.

i have had similar happen to me few times ,when out on club rides ,normally when it happens i have a really strong ride repeatedly being able to race up hills and not getting tired etc normally feel good for a day or two after as well ,then bump cold / flu or some other virus ,maybe its the body prepareing to deal with virus

I don’t think it canbe the HRM.

Probably run/down, overtrained etc.

Not Fresh.

From my experience, if you aren’t fresh you can’t push yourself as hard. You might not be ill or run down, just not ready to go that hard.

SB