Zone 2 at age 38 explained
Zone 2 is easy, conversational aerobic exercise — the intensity that builds endurance with little fatigue. It is usually defined as 60–70 % of maximum heart rate. Because max heart rate falls with age, so does the Zone 2 range. At 38, the Tanaka equation estimates a man’s max heart rate at 181 bpm and the Gulati equation estimates a woman’s at 173 bpm, giving the ranges above.
Individual max heart rates vary by 10–15 beats around these estimates, so treat them as a starting point. If your breathing feels laboured or you cannot speak in full sentences at the top of the range, you are probably above your personal Zone 2.
All five heart rate zones at 38
| Zone | % max HR | Men | Women |
|---|---|---|---|
| Z1 Recovery | 50–60 % | 91–109 bpm | 86–104 bpm |
| Z2 Aerobic / Easy | 60–70 % | 109–127 bpm | 104–121 bpm |
| Z3 Tempo | 70–80 % | 127–145 bpm | 121–138 bpm |
| Z4 Threshold | 80–90 % | 145–163 bpm | 138–155 bpm |
| Z5 VO2max | 90–100 % | 163–181 bpm | 155–173 bpm |
Zone 2 by resting heart rate (Karvonen)
The Karvonen method uses your heart rate reserve (max minus resting), which accounts for fitness. Find your resting heart rate — measured in bed on waking — in the left column:
| Resting HR | Men (Zone 2) | Women (Zone 2) |
|---|---|---|
| 50 bpm | 129–142 bpm | 124–136 bpm |
| 55 bpm | 131–143 bpm | 126–137 bpm |
| 60 bpm | 133–145 bpm | 128–139 bpm |
| 65 bpm | 135–146 bpm | 130–140 bpm |
| 70 bpm | 137–148 bpm | 132–142 bpm |
| 75 bpm | 139–149 bpm | 134–143 bpm |
How to train in Zone 2 at 38
- Make most runs easy: for most runners, three or four Zone 2 sessions a week plus one harder session is a sound structure.
- Go by effort on hot days and hills: heart rate rises with heat and gradient, so slow down or walk to stay in range.
- Track progress: note your pace at the middle of your Zone 2 range once a month — it should get faster as aerobic fitness improves.
- Be patient: Zone 2 often feels slow at first; improvements usually show within 8–12 weeks.
Health first. If you have a heart condition, take medication that affects heart rate (such as beta-blockers), or are new to exercise, ask your doctor which heart rate range is right for you.
Zone 2 at nearby ages
Formulas: Tanaka et al. (2001), Gulati et al. (2010), Karvonen et al. (1957). Last reviewed September 2026. Health disclaimer