Low heart rate with hard sessions


I have trained a lot the last few months. I think I have a very good base built. The last month I started noticing it takes a super hard effort to get my HR above 160. Where the last years I know I can get up to 170/175 HR very fast with a max around 180/185. I’m 38 years old. I’m not overtrained as far as I know. I feel good, I have a normal minimum night HR of 42/43 most of the time. Garmin stats all say I am well rested and ready to train.

How come it is so hard to get my HR up? Or is this normal if you trained a lot in the LSD. I do running interval training for my marathon. So it is not that I don’t do any hard work.

Is this normal when you have a good base built? Or should I start to do some bit more interval stuff? Or should I be worried?

Any tips or experiences here?

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Low heart rate and easily passing the workout is a good thing, you got stronger
Failing a workout with high heart rate, good but the workout was just too hard
falling a workout with low heart rate-> tired or even overtrained


Not sure that’s always true. I muscled my way through 3 sets of 30/15s the other day and spent only a handful of seconds above 90% of HR Max.

My post-ride comment was “Good workout for my anaerobic capacity. Not so good for my VO2 Max. Do it after a rest day next time!”

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For me, inability to bring my HR up is often a sign of impeding illness or at least tiredness.

How’s your resting HR? Elevated resting HR can mean the same thing.

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Heart rate that doesn’t climb to where you expect it/have seen it is a classic symptom of tiredness. How’s the sleep.

Did the same workout today after taking yesterday off. HR in the efforts 5 or 6 BPM higher. 15 minutes above 90% HR Max :+1:

HR is not a super great measure as it can vary for so many different reasons - training load, hydration, heat, etc.

I personally find my HRMax can change by over 20bpm depending on varying factors. The largest factor for me is plasma/blood and stroke volume changes that come from heavy training loads. Aka, training heavy then suppressed HR. Doesn’t mean I’m fitter, it just means my heart is pushing more blood per beat.

My resting HR is the same as always. Lower end. Around 42-44. I sleep well. Most of the timeI feel good in the morning. Training is going well. Only going above 90% max HR is almost not happening during workouts. Sunday I did the “uber pretzel” on zwift. Made a max effort in the end and max HR was 165. Maybe normal after a long (5h00) workout.

On 24th of february I did a cyclocross race. Max HR was 173 (95% of max HR). So it is not broken I think. Gonna take blood test tomorrow. Probably nothing to worry about. I think I need to do a bit more intervals on the bike maybe to get the HR more responsive maybe?