Cold and snow don’t mean I can’t ride anymore – I just move indoors!
I rode for two hours today and played around riding at different intensities to see how my heart rate and perceived exertion were affected. While riding the ‘blue line’ at 20 mph, my heart rate was just under 125 bpm. Increasing my speed a mere two miles per hour resulted in almost a 10 point increase in my heart rate (to 134-137 bpm). I’ve read information recently stating that to increase your speed from 20 mph to 26 mph you have to DOUBLE the your output power!!! Much of this additional power is needed to overcome the greater air resistence at the faster speed (and, obviously, this is a non-linear relationship). but still — twice as much effort for a lousy 6 mph! That’s really rather mind boggling!!
Back to my intensity experiement. When I dropped down two miles per hour, to 18 mph, my heart rate dropped to the 112-115 range. I’m sure that although this appears to be a linear relationship that over the entire spectrum it is not. But, within the small range that I played with it did appear somewhat linear. I could probably ride all day, day after day up to 19-21 mph. Above 135 bpm I am probably transitioning away from fat as a fuel and moving to carbohydrates (and over an extended period perhaps some protein) burning. I have recently become intrigued with knowing exactly what my lactate threshold (LT) is, and I may have a series of tests done at the Boulder Sports Medicine clinic that will not only provide my LT, but also provide information about fuel sources at different intensities (heart rates). This information would also help me design a more accurate training plan for the next five months.
I rode at the “blue line” or above most of the 2 hours, but I did drop down to the sprinter’s lane once after I was thoroughly warmed up. I put in 4-5 laps and somewhere in that effort I topped out at 30.7 mph. That’s a new personal best as my previous best was 30.4. Of course, I’ve only recently started tracking my max speed on the track — but I don’t image that I’ll go ALL that much faster so these little incremental improvements are what I expect.