Heart rate 103 on an adult - what does it mean?
A resting heart rate of 103 bpm is above 100 — that is called tachycardia. It is often a temporary reaction (caffeine, stress, fever, recent activity), but if it stays above 100 at rest it should be checked.
Where 103 bpm sits on the adult scale
- Very low
- Low (bradycardia)
- Slightly low
- Normal
- Elevated (tachycardia)
- High
- Very high
What a resting pulse of 103 means
Common temporary causes: caffeine or energy drinks, nicotine, alcohol (also the day after), stress or anxiety, fever or infection, dehydration, a large meal, heat, pain, and recent physical activity. Decongestants, asthma inhalers and thyroid medication can also raise the pulse.
Sit quietly for five minutes and measure again. If your resting pulse is repeatedly above 100, causes worth checking include anemia, an overactive thyroid, heart rhythm disorders such as atrial fibrillation, and low fitness after illness.
Ranges apply to adults and children aged 10 and older, measured at rest (American Heart Association). By the numbers: at 103 bpm the heart beats about every 0.58 seconds — roughly 148,320 beats a day.
103 bpm during exercise
During exercise a higher pulse is expected. This table shows which training zone 103 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) | 103 bpm is | Training zone |
|---|---|---|---|
| 20 | 200 bpm | 52% | Zone 1 · Very light |
| 30 | 190 bpm | 54% | Zone 1 · Very light |
| 40 | 180 bpm | 57% | Zone 1 · Very light |
| 50 | 170 bpm | 61% | Zone 2 · Light |
| 60 | 160 bpm | 64% | Zone 2 · Light |
| 70 | 150 bpm | 69% | Zone 2 · Light |
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.
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Nearby values
Measured on a child instead? See heart rate 103 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.