Episode 53 of the Performance Advantage Podcast talks about training zones; Dr. Will, and Dr. Matt, teach you how to calculate your training zones as well as breaking down the science of each of the five fundamental zones.
In addition to the five fundamental training zones, there are zones six & seven which are neuromuscular a are more for post-workout analysis rather than workout prescription:
Zone 1: Active Recovery
Zone 2: Maximal Aerobic Function
Zone 3: The Grey Zone
Zone 4: Lactate Threshold
Zone 5: VO2 Max
Zone 6: Anaerobic Capacity
Zone 7: Neuromuscular Power
For a weekend warrior, one who mostly exercises one or two times a week, the specific data on this chart would not be something that you would want to focus on.
As what Dr. Matt said in the podcast:
"It's really easy to see that it gets murky really, really quickly. So zones are a really good way to prescribe exercise because you know what to do, and over time you learn how it feels. And it's super simple for an athlete and a coach to communicate, and to analyze information when we know these discrete zones. But I don't think we need to think about them so specifically and put so much importance on these super, super specific numbers. They are a zone and this is, as we talked about, this is how energy systems work. They're on a kind of this continuum, and they don't start and stop at 56%, your lactate threshold. So this is for any sport."
The important thing to remember with training zones is how your body's energy system function for each level of the zone. You should also take into consideration the purpose of your exercise, or exercise training when you use the training zones as a reference point.
In zone one (1), we were relying on our oxidative metabolism which means that we used fat as a source of fuel in this stage. If we compare it to zone five (5), where glucose is our main source of fuel, we can see the two complete opposite ends of a continuous spectrum.
However, if you wanted to still use fat as a fuel source, and expend more energy while doing it, then zone two (2) would be your standard training zone because zone two enabled you to generate higher output of energy. It also represents "the highest rate of work where we're relying predominantly on oxidative metabolism."
In short, zone 1 = fat as fuel & less or small effort, and zone 2 = fat as fuel & more effort than zone 1.
As Dr. Will described, zone three (3) is called "the grey zone" because it is not zone two so it is slightly above your aerobic capacity but it also does not reach zone four where your lactate threshold is situated.
This is the zone where it's not fully aerobic, but then there's not a point where lactate accumulates. Zone four (4) is called "the lactate threshold", which is where your energy system cannot accommodate the buildup of the hydrogen ions produced with the lactate generated by your energy system. They discussed that lactate in itself is not bad, and it can be used by your body as an additional fuel source.
The real burglar would be the hydrogen ions that was produced by the body when generating lactate that was causing the person's body to reach their limit because your muscles, and its' cells cannot exist or function properly in that acidic state.
Lastly, zone five (5) was identified as your "VO2 Max". Dr. Will pointed out that this zone was what people would thought of as interval training. And I think Dr. Matt summarized what zone five and above actually is:
"It's like pretty much anything above lactate threshold. And this zone, for me, what I do in training peaks, I pretty much just delete any zone after zone five, and then make them all zone five. Because if I'm prescribing something at a maximal level, which is the only other zone that I'm going to prescribe above zone five, I'm just writing maximal and those are so short, it doesn't hardly factor in to a zone and you're just going all out. And we do them pretty infrequently."