After training for about two months focused on power zones (particularly zone 2) I’ve realized that watt-based training has a very significant flaw—especially for older and normal people. This disadvantage is brilliantly summarized on https://hamiltonsports.com:
While training using power has its merits it also comes with an often overlooked disadvantage. The sessions’ power output targets are pre determined post fitness testing. The athlete has a prescribed wattage which they need to hold during each session of their training plan. The sole focus is to stick strictly to these wattage prescriptions. The issue is that watt training does not factor in readiness to train or physical state. For example an athlete may have a poor nights sleep or be particularly stressed due to some lifestyle factor like work etc. he may even be fatigued from a previous training session. When this athlete comes to their training they might struggle to maintain the prescribed wattage but force themselves to be strict. This can result in a much higher level of physiological stress or intensity than intended when their program was designed. Too many forced sessions can result in overreaching and eventually overtraining. It can also be mentality hard on an athlete to realise they cannot keep up with their training. Things can quickly become counterproductive.
This is a significant enough problem to make anything but heart rate training idiotic unless a person is specifically training for a targeted performance at one or more events, which does not describe most people. Those seeking fitness—free from obsession about performance—should definitely not focus on FTP and watts at all.
Why all the obsession about this? Because after going on a 2-hour, 40 km ride on a very hot and humid NC Summer day I noticed a large discrepancy between my average heart rate zone (tempo) and power zone (zone 1/2). My resting heart rate for the day was around 55 so I absolutely know that I’m well rested. My nutrition is fine, not as many carbs as I’d do for a more intense effort, but still fine. I was hydrated (at the start). So I decided to do a little bit more digging.
Watt training is completely broken for older people. We have lower maximum heart rates which blow the scale completely away of watt zone training, even if my 180 max heart rate (supposedly for a 40 year old even though I’m 55).
So I’m changing my power meter on my bike computer so more prominently display heart rate and will be using perceived exertion more. I had already started to do that on my indoor rides, same for outdoor where the stress on my body is so dramatically different depending on the weather conditions.