yesterday was my first sweet spot workout. 4x10 minutes. Hard but not over the top. This morning was 90 minutes near the top of zone 2. From a power perspective, the workout went as planned. However, the second half of the workout this morning, my heart rate drifted up into zone 3 a little. Is that normal after a harder workout the day before or do I need to take another look at my heart rate zones?
It is normal and happens with fatigue. As you become more aerobically fit you should see less of a drift. Typically you may not see as much as a drift in a short zone 2 ride. I’m also assuming this wasn’t your first zone 2 ride so you should compare to other zone 2 rides.
Doing a long zone 2 day fresh is a great way to test your aerobic fitness. You can see where your heart rate starts to drift up riding at a similar power. See how long into the ride it happens. Further you can go without much drift the more aerobically fit you are. Though you have to be careful as heat, caffeine and other factors go into heart rate.
That makes sense based on the temps in the house this morning and the green tea just before I hopped on the bike. I didn’t think about the heat being a factor but it was way warmer than I usually have it. I figured it was Z2 so I let it ride rather than get off the bike and turn on the fan and turn down the furnace…my heart rate went up right around the time my wife woke up and turned the oven on.
Yup indoors with no fan that is probably the biggest factor! I speak from experience. I’ll try to finish zone 2 without as I’ll never start with it on with any ride. But usually after 10 minutes I’m ready.