Lower HR on trainer than out on road?
 

I've been seeing a common pattern where my HR is often lower on a gym trainer than out on the road for the same perceived effort. For example, I could be cruising along on the road at 160 bpm all day long, but on the trainer, any 160 bpm effort longer than 30 minutes would beat me up.

I suspect it's because my HR is higher on the road because I'm always watching out for cars and traffic (and other riders in front of me in a paceline), so that throws in 5-10 extra bpm into the equation even when I'm not putting out extra effort. Whereas on the trainer I don't have to worry about any of that so my HR is lower for equal perceived effort.

Similar experience for you?

No. I will typically see higher HRs indoors for the same perceived effort, probably because riding at 20mph generates more effective cooling than is available in a gym or wherever. I suspect that when you are outdoors you are actually working harder than when in the gym, but feel less stressed because you are concentrating on stuff other than just how you are feeling.

The wind resistance for one would account for the higher HR. Plus, the road gives you breaks that you don't even realize you are getting. I learned that while try to maintain a certain power number and the road dipped down and my power dropped and I would not have noticed so much if I was not trying to stay at that output.

While on the rollers, I can be zoned out at any HR and then if I think about racing and run through some old races in my mind, my HR goes up 5-10bpm. It's funny but I don't want it to happen as I am sending my training numbers to my coach.

Many people find it more difficult to ride a trainer indoors. Lower inertia, fixed position etc. The result is that for a given power level the perceived exertion is higher. If your perceived exertion indoors is the same as outdoors it's quite likely you are putting out less power, hence the lower HR.

I'm much lower indoors, I figure it is because the rest of my body is relaxed. I think the trainer can be harder, and I get more tired from it, but my HR doesn't go as high.

Sometimes I think the HR outdoors is higher from static electricity or other "wind" effects. I get days for sure were this is true; coasting at 240 bpm...

Mines lower on the trainer by 5-10 bpm for a given RPE. I've heard it proposed that it may be due to the reduced inertia of the trainer and subsequent necessity to power through a greater portion of the pedal stroke.

Whatever the cause, there is definately a difference between riding the trainer and riding on the road and how my body responds. But, that shouldn't come as any great surprise.

I don't use as many muscles on the indoor trainer at the gym. I feel like I am working very hard at 130bpm. Outdoors, I don't get that sensation until I get 160bpm.
Indoors I am not balancing around corners, wrestling the bike up hills, twisting around looking for approaching cars, signaling turns.

The flywheel on the indoor trainer forces a too-low resistance due to some bad knee issues that create dead spots in my pedal stroke.
On the road, I get some forgiveness for my inherently uneven application of force and can handle the bigger gears. The higher resistance recruits more muscle fibers.

Funny I just saw this thread and I've been thinking about this exact situation lately! I don't have a HRM, but I'm hyperaware of what my body is doing at all times and I can definitely feel a lot more adrenaline and endorphins pumping through my body when out on the roads for obvious reasons (butt loads of CLOSE traffic whizzing on NO shoulder roads, lots of road hazards, other cyclists getting close and causing me to stay very aware of my immediate surrounds, etc.) and my personal home indoor trainer is just that, a safe, sturdy indoor trainer. I want to eventually get a HRM, but that will be my very last upgrade.

If you're upgrading for any sort of performance reasons, it should probably be your first.

I'm not going for the gold on any races for a while and if I do race, I'm just in it to come in around a decent time (I guess that means NOT LAST). I've only been cycling for a year and I have the cardiac health since I've been a runner my entire life (36 y/o), but I haven't started training just yet. I know that my average pace stays around 17-18 mph. That's as far as I've gone to meet any kind of standards right now.

I'm currently at my ideal medical weight and I lost all the weight cycling, so I know I'm doing something right because I used to be 55lbs heavier. I lost all the weight at a decent rate as well because it all came off within a year, so 55lbs dropped in one year. I guess the HRM will become a valuable tool once I get into all of those details, but I'm enjoying just pushing myself hard enough to know that I'm getting a good cardiac workout. I'd honestly rather get a better set of wheels (Zipps), Camagnolo "Record" or "Chorus" gruppo, Shimano "Dura Ace" or something along those lines. I currently have my stock Shimano 105 groupset and I LOVE it, so I'm excited to see how Campy or upgraded Shimano will feel.

lots of things affect HR not just perceived effort