Resting heart rate changes the meaning of a workout number.
A heart rate of 145 does not mean the same thing for everyone. If one person rests at 48 and another rests at 78, the same workout heart rate sits in a different part of their usable range.
That is why Zonas uses resting heart rate when it can.
Where It Comes From
Zonas reads resting heart rate from Apple Health.
The current app does not ask you to type in a resting heart rate manually. That is deliberate. A real HealthKit value is better than a guessed value, and a missing value is better than false precision.
The 14-Day Median
When Zonas refreshes resting heart rate, it looks back 14 days.
Then it sorts the available samples and uses the median.
That is a small but important choice. Resting heart rate can move with sleep, stress, illness, alcohol, heat, and training load. The newest sample may be useful, but it can also be a weird day. A median smooths that out without hiding the value behind a complicated model.
How It Changes Zone Math
With resting heart rate, Zonas uses heart rate reserve:
reserve = HRmax - RHR
target = RHR + intensity x reserveWithout resting heart rate, Zonas falls back to percent of max heart rate:
target = intensity x HRmaxThe fallback is simpler. It is also less personal.
What If It Is Missing
If Apple Health has no resting-heart-rate samples, Zonas does not fill in a population average.
It uses percent-HRmax zones instead.
That is the honest tradeoff. A guessed RHR would make the calculator look more personalized while making the data less trustworthy.
How To Improve It
If you use Apple Watch, wear it consistently enough for Apple Health to produce resting-heart-rate samples. Overnight wear usually helps, because the quietest heart rate data tends to appear outside workouts and daily movement.
Then refresh in Zonas settings.
If the app still cannot read the value, check Health permissions. Zonas needs permission to read resting heart rate from Apple Health.
What It Does Not Mean
Resting heart rate is useful context. It is not a full readiness score.
Zonas uses it for zone calculation. It does not infer whether you are sick, recovered, overtrained, or ready for a hard workout.
Common questions
Can I type resting heart rate into Zonas?
Not in the current version. Zonas reads resting heart rate from Apple Health. If it is missing, automatic zones use percent of max heart rate.
Why does Zonas use a median?
A median is less sensitive to one unusual day. The app looks at the last 14 days of resting-heart-rate samples and uses the median value.
Do I need an Apple Watch for resting heart rate?
Apple Watch is the common way to get Apple Health resting-heart-rate samples, especially if you wear it overnight. Zonas reads the HealthKit value when it exists.
Sources
- restingHeartRate
HealthKit exposes restingHeartRate as a quantity sample type for resting heart rate values.
- Monitor your heart rate with Apple Watch
Apple Watch measures heart rate during workouts and also calculates resting and walking heart rate values from background readings.
- View Heart Rate Zones on Apple Watch
Apple Watch zone personalization uses personal health data such as resting heart rate and maximum heart rate.