Health note
Zone 2 training, explained
Slow down most of your cardio. It is the part of exercise you can keep doing for decades.
The short answer
- Zone 2 is steady, easy cardio: you can talk in full sentences, but not sing.
- Find your heart-rate ceiling with 180 minus your age, adjusted for your health and training, and build toward 120 to 150 minutes a week.
Zone 2 is the cornerstone of the exercise prescription I recommend: 120 to 150 minutes a week of steady, easy cardio. Patients often ask what it means and how to know they are in it. Here is what it means and the method I use.
What Zone 2 means
Heart rate "zones" divide exercise effort into bands, from very easy to all-out. Zone 2 is the second band: moderate effort you can hold for a long time. A simple check is the talk test. You should be able to speak in full sentences, but not sing.
For most people, that means brisk walking, an easy jog, steady cycling or swimming, or hiking at a pace where you aren't gasping. If you're new to exercise, a brisk walk may already be Zone 2. That's fine.
Finding your Zone 2 heart rate: 180 minus your age
I use Dr. Phil Maffetone's 180 Formula because it is simple and needs no lab test. Subtract your age from 180, then adjust:
| Your situation | Adjustment |
|---|---|
| Recovering from a major illness, surgery or hospital stay, on any regular medication, or in rehabilitation | Subtract 10 |
| Just starting or getting back into exercise, injured, not improving, getting more than two colds or flu a year, or have asthma or seasonal allergies | Subtract 5 |
| Training consistently (at least four times a week) for up to two years without those problems | No change |
| Training for more than two years without those problems, and still improving | Add 5 |
Example: a healthy 40-year-old who has been exercising regularly gets 180 − 40 = 140 beats per minute. Keep your heart rate at or a little below that number during Zone 2 sessions. Maffetone notes the formula may need more individual adjustment after age 65, and it doesn't apply to athletes 16 and under.
The formula is a practical rule of thumb, not a precise lab measurement. If the number feels far too easy or too hard by the talk test, tell me and we'll adjust it together. Some medications, like beta blockers, change how your heart rate responds to exercise, so check with your doctor before using heart rate targets if you take one.
Why easy cardio works
It can feel too slow to matter, but two lines of evidence support it.
First, moderate activity is strongly linked to living longer. A pooled analysis of about 661,000 adults followed for a median of 14 years found that people who met the minimum recommended amount of leisure-time activity had a 31% lower risk of death than people who did none. At three to five times the minimum, the reduction was 39%. Even people doing some activity, below the minimum, had a 20% lower risk. These were observational studies, so they show an association rather than proof, but the pattern is large and consistent.
Second, the best endurance athletes train mostly easy. A review of how elite endurance athletes train found that about 80% of their sessions are at low intensity, with a smaller share of hard interval work. If easy training builds the base for Olympians, it can build yours.
Easy training also has a practical benefit: you recover quickly, so you can do it again tomorrow. Consistency over months matters more than any single hard workout.
How to start
- Use a watch or chest strap that shows your heart rate while you exercise.
- Start with 20 to 30 minutes, three times a week. Walk the hills if you need to stay under your number.
- Build toward 120 to 150 minutes a week, spread over several days.
- Keep two or three short strength sessions in your week too.
- Expect your pace at the same heart rate to improve over a few months. That's your aerobic base growing.
Living in Colorado Springs? Altitude can make the same pace feel harder, especially on a trip up into the mountains, so go by heart rate and the talk test rather than pace. My guide for athletes and active adults has more on training at altitude.
If you have heart disease, chest pain with exercise, or another serious condition, talk with your doctor before starting a new exercise plan.
Sources: Maffetone P. The MAF 180 Formula: heart-rate monitoring for real aerobic training. philmaffetone.com. Arem H, Moore SC, Patel A, et al. Leisure time physical activity and mortality: a detailed pooled analysis of the dose-response relationship. JAMA Internal Medicine. 2015;175(6):959–967. doi:10.1001/jamainternmed.2015.0533. Seiler S. What is best practice for training intensity and duration distribution in endurance athletes? International Journal of Sports Physiology and Performance. 2010;5(3):276–291. doi:10.1123/ijspp.5.3.276.
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