Power meter vs. heart rate monitor.

[Rock Creek Rider]

Power meters seem to be the big thing right now. Until their price goes down, I won't be getting one, but are they really better for training? The argument for power meters is that they show changes in effort almost immediately, whereas your heart rate lags behind. Also, your power output isn't affected by temperature and caffeine intake, like your heart rate is. By that, I mean if you are making 120 watts, it's 120 watts no matter what the temperature or what you've been eating.
The problem I see with the power meter, other than the cost, is it isn't showing what is actually going on with your heart, which could be dangerous. And, as far as I know, I could be wrong, it doesn't show when you are entering your lactate threshold and anaerobic threshold, or you are approaching you maximum heart rate. I would think these are still important things to know. As far as your heart rate lagging behind what you are doing, I just anticipate that. So, if I want to increase my heart rate up to a certain number then let my heart rate go back down to a lower number to recover from the effort, I just ease off before my heart gets to the higher number then start pushing a little harder before it gets down to the lower number I want. As far as the heart rate being affected by temperature and caffeine, etc., I'm not sure it matters. I think you probably want to use the same target zones no matter. Does lactic acid start building up at a different heart rate depending on temperature or what you've ingested? I don't know the answer to that, but I doubt if it makes much difference over an extended period of time. I think it all balances out.
I think it would be best to use the two together. I think you could learn a lot from that.

 

[Yojimbo_]

If you use the power meter properly, you will know what your various threshold values are and you can therefore ride accordingly.

The thing with heart rate is that it drifts so that at constant power output your heart rate will drift upwards. This means that if you were riding to keep your heart rate constant, your work rate would be decresing with time. Heart rate also lags when you increase your work rate so it's not helpful for very short very hard intervals.

For casual riders this doesn't matter but if you are wanting to train and get faster and fitter, it does.

There are many resources and much information available on training with heart rate and power meters on the web. Here is something from The Sufferfest.

thesufferfest.com/blogs/training-resources/heart-rate-and-training-everything-you-ever-wanted-to-know-but-were-afraid-to-ask

 

[Cyklopedia]

Hi, I would say you should focus on the relationship between power and heart rate, then you can really analyze data. You can work out with heart rate only or power only but it doesn't give you the whole picture.