Heart rate mismatch between biking/running

Hi there, I have been noticing that my heart rate seems to be fundamentally different between biking and running.

On runs, even at long race-pace efforts, my heart rate average will hover somewhere between 160-170bpm. And I can stay at this level of intensity for 90-120min. On the other hand, on my bike rides I am hard pressed to push my heart rate up to 160 bpm for anything other than high-intensity efforts of a few minutes (5 min or less). Anything beyond that and my thighs start burning to the point that I have to slow down.

I’m wondering if this means that my overall aerobic capacity and with it the oxygen flow driven by the heart rate is really not the limiting factor on the bike? Would this suggest that I should focus more on high-intensity training for shorter intervals to increase overall power output/FTP and focus a little less on longer/endurance rides?

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It’s quite normal for running HR to be a fair bit higher than cycling. Because it is weight bearing, there are more muscle groups involved, and most people find they will be able to sustain higher HR when running. How much higher depends on the individual.

One minor question, how are you measuring HR for running and cycling? (just because 160 sounds pretty close to a running cadence, and my old optical HR sensor often locked onto my strike rate)

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I’m using the Garmin Tri Heart Rate Strap for both. My running cadence is quite high at close to 180 on my last half marathon training run. So I do not think there is any interference/confusion between the two.

And I guess I understand that running and biking are quite different in terms of muscle use: While in biking all energy output (and with it oxygen consumption) comes from my legs – the thighs mostly, in running it’s much more of a ‘whole body’ effort.

My question is really aiming at what specifically to train for on the bike though to maximize improvements. It seems that aerobic capacity on the bike is really not the issue for me–rather it’s a question of ‘how do I churn through more energy/oxygen’ so I can actually make use of my aerobic capacity. So with that, should I focus more on high intensity efforts above FTP to increase my power output? Maybe even couple this with specific leg strength exercises to build more muscle?

The HR strap won’t be an issue then, it was just a thought.

Personally, I would view the two separately and do my cycling training based on power. HR isn’t super important if you have power, so there’s no real value comparing them between running and cycling except for interest. And I would train based on trying to improve my power over the durations and repeatability I am interested in (i.e., based on the demands of the event, or just the type of riding I like to do). What you’re describing sounds like trying to improve power at VO2 max (= maximum aerobic capacity) - and yes, work above FTP is a good way to do that. A TR plan like Short Power Build is good for that, although I would work through Base first depending on where I was (or just do a Plan Builder plan with one of the short power type events as a target).

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Thanks for continuing to weigh in.

To give more context. I’m 49 and two years ago decided to enter my first Tri (70.3). I ended up doing reasonably well (3rd in my age group) and got really motivated to continue with the sport. I will compete in my 2nd 70.3 next week and I am hoping to complete my first Ironman when I’m 50.

In general (based on both perception and my ranking in the field of the last Tri) I am average swimming, a poor runner, and a well-better than average cyclist. I am focusing a lot on running in the past year and hope to push my half-marathon time to 1:45. I did get stronger on the bike as well, but I am now thinking about how to adapt my training to be much more targeted on the bike. That’s why I started thinking about what I actually need to improve (aerobic capacity/VO2 max vs. power output/FTP).

A little bit further context: I am not really exclusively focused on the mid- to long-distance Tri. I also competed in a couple of short efforts (Sprint Tri and 5K/10K runs), but also on endurance events (100mile rides, long Gravel Grinders). And this year I will also try to do the Spartan Trifecta. So overall I am quite active, do tons of cross-/strength-/flexibility-training, and do not really want to laser-focus my training on a specific event or short-coming.

Yep, run HR is generally 5-10bpm higher for the same effort level running than it is for cycling, and you’ll probably notice a difference in sustainable heart rates for the two. Other people have mentioned muscle recruitment, but weight/gravity plays a factor too- swimming will typically be the lowest of the three. If HR analysis is a significant consideration in both sports, I’d recommend doing a separate test to determine your zones for each.

Regarding what to work on- I understand your focus is very broad, but performance is largely relative to your goals, and generally this entails working on all of your energy systems as part of a periodized plan towards a specific end. Doesn’t have to be an event, but ‘targeted’ training on the bike is best approached with, well, a target.

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I would caution against making direct comparisons between heart rates while running vs cycling. A runner trained in both disciplines will almost invariably have a higher heart rate while running. It is a weight bearing exercise and presents different demands on the aerobic system. When reviewing your heart rate on the bike you should be focusing more on elements like cardiac drift and recoverability than raw HR values. What’s happening to your HR at hour 1, 2, 3 etc… is it climbing? This is where endurance work is pivotal. Building those fatigue resistant slow twitch muscle fibers will allow you to work in your aerobic zone longer without drawing on Type 2 (less fatigue resistant) muscle fibers. It’s when you start to tap into those fibers that you start to break down. That’s the limiter, not heart rate.
Your heart rate is a measurement of strain, not stress. It could be a leading indicator of fatigue and there is much to be gleaned from it, but to look at it as a factor that could “limit” your performance on the bike is an approach I would recommend against. If you have weaknesses in your profile at the higher zones, that would be a driver to incorporate additional high intensity in your plan. However, trading off endurance for intensity based on comparing your heart rate between disciplines will likely lead you down a less productive path.
Hope this helps.

I don’t know much about it but I note Garmin has different profiles for running and cycling activities so I guess its normal to have a mismatch.

My N=1

My running HR is about +10 bpm higher at the same effort… probably closer to +15
My 5k, strong finish HR is (was) about 201 or so back in 2018. I can hold this for probably a minute or so… at 195 I can hold for close to a mile ( < 6 mpm) during a 5k race… no more than that. this is legs and arm tingling HR, not just uncomfortable…
On the bike, the highest Ive seen has been on a ramp test probably last year… 191… and it felt horribly bad…

I have never meet anyone who has the same cycling and running HR.
I wouldn’t worried to much about it.

There’s a lot of info here to digest. I will review and think a little more about what I am trying to achieve and work toward–and with that reconsider on how to best get there.

Thank you.

Again, thanks for your thoughts. Similar to my reply to Sarah, I will consider what you wrote, get more clarity on what I am trying to achieve, and then decide on what to do in order to get there.

I very much appreciate your help.

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