Heart rate 170 on an adult - what does it mean?
A resting heart rate of 170 bpm is very high. During hard exercise it can be expected (see the training table below) — at rest, a pulse this fast needs urgent medical attention.
Where 170 bpm sits on the adult scale
- Very low
- Low (bradycardia)
- Slightly low
- Normal
- Elevated (tachycardia)
- High
- Very high
What a resting pulse of 170 means
At rest, a sudden racing heartbeat of 170 bpm is usually not ordinary sinus rhythm. Typical causes are supraventricular tachycardia (SVT), atrial flutter or fibrillation, and — less often but more dangerous — ventricular tachycardia.
Also double-check the reading: wrist devices can lock onto your movement cadence during exercise and report it as heart rate.
Ranges apply to adults and children aged 10 and older, measured at rest (American Heart Association). By the numbers: at 170 bpm the heart beats about every 0.35 seconds — roughly 244,800 beats a day.
170 bpm during exercise
During exercise a higher pulse is expected. This table shows which training zone 170 bpm corresponds to, based on the common estimate of maximum heart rate (220 minus age). Individual maximums can differ by 10–20 bpm.
| Age | Est. max (220 − age) | 170 bpm is | Training zone |
|---|---|---|---|
| 20 | 200 bpm | 85% | Zone 4 · Hard |
| 30 | 190 bpm | 89% | Zone 4 · Hard |
| 40 | 180 bpm | 94% | Zone 5 · Maximum |
| 50 | 170 bpm | 100% | Zone 5 · Maximum |
| 60 | 160 bpm | 106% | above estimated max |
| 70 | 150 bpm | 113% | above estimated max |
How the zones work: Heart Rate Zones: The 5 Training Zones by Age.
How to get an accurate resting reading
- Sit or lie quietly for 5 minutes. No caffeine, nicotine or exercise in the 30 minutes before.
- Place two fingertips (not your thumb) on the inside of your wrist below the thumb, or gently beside your windpipe on one side of the neck.
- Count the beats for 30 seconds and double it — or count a full 60 seconds if the beat feels irregular.
- Repeat on a few mornings before getting up and use the average.
Already have the number? Check another reading or measure by tapping along on the start page.
Check another reading
Nearby values
Measured on a child instead? See heart rate 170 in a child.
This page explains a single reading in general terms. It is not a diagnosis. Heart rate alone cannot tell whether the rhythm is regular or whether the heart is healthy — if you are worried, talk to a doctor.