A recent achilles injury has stopped me running at the moment so I have taken to the bike to try to retain some fitness. However I am very confused – I can comfortably run for >1hr and stay in my peak zone for the entirety of the run (averaging around 165bpm) however doing a similar length of time on a bike feels equally strenuous (ie, I will ride as hard as I feel I am able for the duration and don’t coast at any point) but my average bpm is more like 125bpm (occasionally topping out at 160 on steeper hills) and spend about 50% of the ride just in my cv zone. Can anyone explain why this is as I am very confused because I don’t think I could push any harder without blowing up.

I find similar, on the bike outdoors I struggle to get my HR up to any kind of sensible level. I put this down to the fact that I recover well so my HR drops as soon as the road points down hill.

On the turbo I can get closer to the right numbers but am a right mess at the end.

I’m sure I read something that you HR is higher running as you support your own weight. Could be rubbish though.

Your hour threshold HR for the bike is 125bpm and you don’t feel like you can push any harder?

Come on now John – you’re not dead yet.

Enter a club ten (ideally a 25 but 10s are much more common on weekday evenings) on the fastest bike you own to get some incentive to pedal hard. Then see what the HR does.

Like Garry says get on a TT in an evening or get ready for the coming CX season, that’ll get your HR up even if you don’t want it to!

I find that running avg heart rate is higher than cycling avg heart rate for what feels a comfortable cracking on pace.

I think it feels harder to maintain a higher heart rate on a bike as you a re simply having to move that much faster, and that can actually be more difficult on country lanes or roads with junctions as you are constantly slowing down/speeding up. Try riding more hills or a 25 mile TT they will certainly get your hear rate up there.

Yup, find a hill and nail it.

But I know what you mean, on the bike on the flat I feel like my leg power gives out before the fuel/oxygen supply, whereas pushing when running quickly produces gasping, snot bubbling anaerobic agony, if that makes any sense whatsoever?

You don’t have to lower yourself to doing a TT or CX race, racing XC would give you an hour or two close to max heart rate as well.

My take on it is that the entry point of effort for running is just higher than mild to moderate cycling, so you don’t really have to try to work hard. It’s compulsory.

I’m the opposite.

I’ve spent over 20 years exclusively mtbing and tried running last autumn. Before I hauled up with all sorts of horrendous calf strains, I found it easy to maintain my HR at threshold (156 in my case) but my legs, entirely trained for circles as they are, were completely rubbish and died in record time.

I found this bizarre scenario were from a cardio perspective it felt like I hadn’t done anything, but I couldn’t walk in straight line due to jelly legs.

Frustrating!

I can sit 10 or less beats below max for ages on the bike, find redlining quite easy. Walking up hill on the other hand, my HR just won’t move at all…..

Always been good at running close to max on a bike eg old NPS XC HR trace from 2007…

[url=https://flic.kr/p/L1HGV]NPS-2 HR[/url] by Ben Freeman, on Flickr

Your hour threshold HR for the bike is 125bpm and you don’t feel like you can push any harder?

Come on now John – you’re not dead yet.

Okay, so I didn’t describe it properly – I feel like I am pushing at the same effort as when running.

Chest strap or optical wrist sensor?

Was going to say chest strap or wrist HRM? I find that my wrist based HRM doesn’t give as accurate a reading on the bike. I can be really pushing it cycling up a hill and the HRM will say 140 or lower and I feel like I’m doing 180. Then all of a sudden it jumps to 180.

Also I find when running my HR is consistently higher than riding a bike. But I think that’s just because I’m lazy and don’t peddle my arse off going downhill 🙂

I have the same and I believe from articles that I have read that it is the norm for a running max heart rate to be higher than a cycling max heart rate. As I am not a sports focused cardiologist I will not try to explain why (that’s not very STW is it?).

Interesting. 125 bpm for me is basically not trying on a bike. I try not to run though

You’re sat down on a bike, it’s far easier on the body than running.

I’m the same as scienceofficer and reckon your cycling legs are weaker than your running heart.

I’m not a regular runner, but whenever I do run my legs are hurting at 10 minute miles while my heart is somewhere between 105 and 125.

Yes I kinda think that is the case – although I have strong running legs, 18 months or so off the bike (I used to do spin classes three times a week before covid) probably just means the muscles used for riding aren’t as strong so takes more effort.