The cardio habit that adds years, not just fitness

DAILY RHYTHM · 4 MIN READ

Zone 2 cardio is one of the simplest longevity habits most people still don't do enough of.

Probably because it feels too easy to matter. Here's how to actually start, and what to watch for in the first two weeks.

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1. 01 Find your actual Zone 2, not your guess. Zone 2 is the effort level where you can hold a full conversation but wouldn't want to sing. Heart rate roughly 60-70% of your max, but that number varies a lot by person. The simplest test: if you can speak in full sentences but breathing is noticeably elevated, you're probably there. A proper baseline assessment using lactate or VO2 data removes all the guesswork and is worth doing once.
2. 02 Start with 20 minutes, three times a week. Not 45. Most Zone 2 programmes eventually work up to around 3-4 hours per week. That sounds like a lot, and if you try to get there in week one, you'll either overdo intensity or quit. Start at 3 x 20 minutes of easy effort: a brisk walk, a slow bike, a casual swim. Stay consistent for four weeks, then build. The important thing at this stage is consistency, not intensity.
3. 03 Don't go too easy either. Zone 2 is often explained as "don't go too hard." But you can also go too easy, basically a slow stroll. If you're barely raising your heart rate, you may not be getting the training effect you're aiming for. You want sustained, mild cardiovascular stress. A wearable helps, but even without one, the talk test is reliable enough. If you're chatting effortlessly on the phone with zero awareness of your breathing, pick up the pace slightly. If you're cutting sentences short to breathe, slow down.

OUR VIEW

Zone 2 training isn't exciting. It is also easy to neglect because it doesn't feel like a hard workout. The evidence for its benefits to cardiovascular health, insulin sensitivity and mitochondrial function is strong. It matters most for people who are already training but skipping easy aerobic work and doing most sessions at higher intensity. Adding two or three Zone 2 sessions per week, alongside your existing work, is one of the simplest changes we make with clients who want to optimise healthspan rather than just fitness.

P.S. What does your current cardio week actually look like? All intensity, all easy, or somewhere in between? Hit reply and tell me — I'd be curious to see what the mix is.

— Emilian