Originally Posted by
Heathpack
Obviously there could be more than one factor operating simultaneously to account for cardiac drift. Does anone here know the relative importance of the heat dissipation component vs the greater muscle recruitment argument in the article? The main reason it is matters is that if it's just a heat dissipation thing, I'm not sure how significant the increased heart rate is. If its a training thing, then it matters quite a bit.
Heat dissipation is clearly a part of the reason but it's not all of it, nor is it a fixed fraction. On a bike on the road, convective cooling dominates, so you will get differential amounts of cardiac drift depending on the weather, the wind, the relative humidity, and what you're wearing. Indoors on a trainer you can see this: at the same fixed wattage output, cardiac drift will vary with what you're wearing, the volume of air being moved past you with fans, and (a little less so) the temperature. Nonetheless, even riding outdoors on a cool day you will experience some cardiac drift over time.
That said, it's not clear-cut that the cardiac drift one encounters outdoors is that closely tied to cadence. It appears to be more closely related to power output (which is, of course, the product of cadence and pedal force). That is, low cadence - low pedal force produces low power, and cardiac drift can be small. High(er) cadence with low(er) pedal force can produce low power, and again cardiac drift can be small. Low(er) cadence with high(er) pedal force can produce low power, and yet again, cardiac drift can be small. Bored yet? However, high(er) cadence with medium pedal force, or low(er) cadence with very high pedal force, or (horrors) high cadence with high pedal force produce high power, and cardiac drift can be large as you fatigue.
Originally Posted by
fietsbob
pick a gear ratio that feels right at the pace you ride over the terrain you confront.
This.