I keep seeing conflicting advice about Zone 2 training intensity. Some people say it should feel "conversational pace" while others give specific power targets.
My numbers:
When I ride at 155W I feel like I'm barely turning the pedals. At 200W it feels "easy" but I can't really hold a full conversation.
Where should I actually be riding for maximum aerobic benefit? And does it matter if I drift into Z3 occasionally on hills?
Great question. The "right" Zone 2 is actually narrower than the Coggan range suggests.
The physiological target: You want to train at the highest intensity where your body is primarily burning fat as fuel, with lactate staying below ~2mmol/L.
For most trained cyclists, this is around 65-75% of FTP. So for your FTP of 275W, that's roughly 180-206W.
At 155W you're in Z1 (active recovery) — still useful, but not providing the same aerobic stimulus. At 200W you're at the sweet spot of Z2.
The conversation test is actually pretty good: you should be able to speak in full sentences but not sing. If you're breathing noticeably, you're too high.
Hills: Brief excursions into Z3 (30-60 seconds on a rise) are fine. The concern is spending sustained time in Z3 when you intended Z2, because it changes the metabolic demand of the ride.
Thanks both — this is super helpful. So I should be riding around 190-200W and monitoring HR to make sure it stays in the right range?
Follow-up: does cadence matter for Z2? I naturally ride at ~80rpm but I've seen suggestions to spin higher (90+) for aerobic development.
I'd add that HR is actually a better metric than power for Z2 training, because it reflects the actual physiological stress.
Aim for 60-70% of your max HR for Zone 2. If you don't know your max HR, use the formula: LTHR × 0.81-0.89 (where LTHR is your lactate threshold HR).
Power is great for intervals but heart rate tells you how your body is actually responding on a given day.
@Jake — Higher cadence at Z2 does shift the load slightly more toward the cardiovascular system (more aerobic, less muscular). But the effect is small. Ride whatever cadence feels natural.
Personally I do most Z2 at 85-90rpm and it feels right. The cyclists who advocate for 95+ rpm in Z2 are usually coming from the old Lance Armstrong school of thought, which has been largely debunked.
Just keep the power steady, heart rate in range, and enjoy the ride. Don't overthink it.
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