The standard formula
CDC describes moderate-intensity activity as roughly 64% to 76% of an estimated maximum heart rate, and vigorous-intensity as roughly 77% to 93%, using the common population estimate that maximum heart rate is about 220 minus your age. This is the same formula behind the 'zones' many fitness watches and gym cardio machines display.
What this does not tell you: why it is an estimate, not a measurement
The 220-minus-age formula describes an average across large groups; an individual's true maximum heart rate can be meaningfully higher or lower than the formula predicts, with no way to know by how much without a supervised test. It says nothing about medicines.
Some heart medicines lower a person's real maximum heart rate, which makes the standard percentages read differently for someone taking them. If you take a heart-rate-affecting medicine, ask your clinician what a reasonable target looks like for you, rather than relying on the formula.
A simpler check most people already have access to
Effort Check uses the talk test and CDC's 0 to 10 effort scale instead of a heart-rate formula, for exactly this reason: it does not require a device, and it already accounts for how an activity feels to you specifically, medicines and all.
If your watch says one zone and the talk test says another, this guide's own advice is to trust how it feels over the number on the screen.
When a heart-rate number is worth watching closely
If your heart rate feels unusually fast, irregular, or does not come back down as expected after you stop, or if you feel chest pain, dizziness, or unusual shortness of breath, stop and get medical advice. That is a different situation from checking which zone a workout falls into.
Try it today
Small, reviewed steps you can start now. Choose one, or save it for later.
Take a comfortable 10-minute walk
About 10 minutes · Easy
Choose a familiar, safe route and walk at a pace that feels comfortable today.
- How to start
- Step outside, pick a familiar route, and set a 10-minute timer. Turn around at the halfway point.
- You will need
- Comfortable shoes and a route you already know.
- How hard
- Easy: a pace where you can still talk comfortably.
- Done when
- You walked for about ten minutes, or as long as felt comfortable.
Involves: being outdoors.
Safety: Use a route and pace that are appropriate for you. Stop for a new concerning symptom.
Evidence strength: strong. General information, not medical advice.
Learn more: Fitness after 50
Take a comfortable 10-minute walk indoors
About 10 minutes · Easy
Walk at a comfortable pace around your home, a hallway, or a shopping center, and stop when the time is up.
- How to start
- Choose a loop indoors that is clear and well lit, and set a 10-minute timer.
- You will need
- Comfortable shoes and a clear path indoors.
- How hard
- Easy: a pace where you can still talk comfortably.
- Done when
- You walked for about ten minutes, or as long as felt comfortable.
Safety: Use a route and pace that are appropriate for you. Stop for a new concerning symptom.
Evidence strength: strong. General information, not medical advice.
Learn more: Fitness after 50