Okay, so now you have determined statistically and using your instincts when you need a little break from intense workouts and rides. I think that as you track data, you start to see the need for variety and rest. There are two distinct “training” situations that I run into all the time: a day when I need to go a little less (or more) intensely and a day where I need to recover.
Variety and LSD
Recall from previous entries that there are really two things that cause training stress: intensity and duration. So, for example, after a hard interval session mid-week, I am going to opt to do a longer and slower ride the next day. I am not going to continue to match the interval session’s intensity back to back too often. For one, it would build up too much training load too fast and secondly, I want to be working different systems. I want to be a well-rounded cyclist, not only focusing on 30 second power but also endurance. So, I will hit it hard one day and then turn around and mix it up with a long easy day.
When I go for the long slow distance (LSD), I track heart rate (and power) and try to keep in zone 2. This endurance zone is one that typically a cyclist could ride all day long. It is one in which you could hold a conversation and manage most hills at a moderately easy feeling pace. ALL BIKE RIDING IS HARD! I don’t look at any other metrics on LSD rides, I just look at my zones and try to keep my efforts in zone 2.
One interesting guideline I use comes from Dr. Phil Maffatone who gives the formula of 180 minus your age as a heart rate for endurance exercise (plus or minus a few points for certain factors, see the link). I have been using the number 135 +/- for a while now, and I know that if I am somewhere between 125 to 135 bpm, I am in the right zone for endurance training. These rides are easy, and they do help you to build fitness and work your endurance system.
I don’t worry as much about power on these rides, and sometimes I ride my steel bike that has no power meter on it. Again, one major benefit of power in training is that it more accurately adjusts to the ups and downs of intense riding, whereas heart rate lags behind. On long slow efforts, this is not a problem in my mind, although it is interesting to see how much more power you can put out at a low heart rate as you get more fit over time.
So, shoot for variety in your training and utilize LSD quite often to keep working on the ever-important base without blowing yourself up all the time.