Heart rate 138 on an adult - what does it mean?

Where 138 bpm sits on the adult scale

What a resting pulse of 138 means

If you just climbed stairs, exercised or are very anxious, a pulse of 138 can be a normal response and should fall within minutes. A fast rate that persists at rest can come from fever, dehydration, blood loss or anemia, an overactive thyroid, or a heart rhythm disorder such as atrial fibrillation, atrial flutter or supraventricular tachycardia (SVT).

An irregular pulse at this speed is a typical sign of atrial fibrillation, which raises stroke risk and should always be evaluated.

Ranges apply to adults and children aged 10 and older, measured at rest (American Heart Association). By the numbers: at 138 bpm the heart beats about every 0.43 seconds — roughly 198,720 beats a day.

In the middle of an episode at 138: a step-by-step plan

People who already know they have supraventricular tachycardia (SVT) usually recognise an episode at once: a sudden click or flip in the chest, then a fast, very even beat. Rates are most often 150 or more, but slower episodes such as 138 happen too. If this is your first ever episode, treat it as unknown and get it checked the same day, or call 911 if you feel unwell. If your doctor has already diagnosed SVT and given you a plan, this is how a typical one looks:

1. Stop and sit or lie down. Note the time the episode started.
2. Record it if you can: a watch or phone ECG, or a photo of the pulse reading. A recording of the actual rhythm is worth more than any description.
3. Try the vagal maneuvers you were taught. These stimulate the vagus nerve, which can interrupt the short circuit.
4. Set a time limit. Your doctor will usually tell you how long to wait before going in, often a short period such as fifteen to thirty minutes.

Vagal maneuvers that doctors commonly teach

The modified Valsalva maneuver. Sitting up, bear down hard as if straining on the toilet, or blow into a 10 ml syringe hard enough to move the plunger, for about fifteen seconds. Then lie flat straight away while someone lifts your legs for about fifteen seconds. Research in emergency departments found that adding the leg lift makes the maneuver work much more often than straining alone.

Cold water on the face. Holding your breath and putting your face into a bowl of cold water, or pressing a bag of ice wrapped in a cloth to the face, triggers the diving reflex that slows the heart.

Do not press or massage the side of your neck yourself. Carotid massage is done only by a doctor with monitoring, because it can be risky in older people.

When the episode will not stop

In the emergency department, staff often try a vagal maneuver again first. If that fails, a medicine called adenosine is given through a vein. It blocks the circuit for a few seconds and often ends the episode at once. It can cause a brief, very strange feeling of chest pressure or doom, which passes quickly. Other heart-slowing medicines or, rarely, an electrical shock under sedation are further options.

Call 911 without waiting for your time limit if you feel faint, have chest pain or become very short of breath, and do not drive yourself. Frequent episodes are a good reason to ask about catheter ablation, which can cure many types of SVT. The heart rate monitors page lists devices that can record the rhythm during an attack.

For a reliable resting value, sit quietly for five minutes first and average a few mornings: Resting Heart Rate: What It Says About Your Health. You can also measure by tapping along on the start page.

Nearby values

• 133 bpm
• 134 bpm
• 135 bpm
• 136 bpm
• 137 bpm
• 139 bpm
• 140 bpm
• 141 bpm
• 142 bpm
• 143 bpm

Measured on a child instead? See heart rate 138 in a child.

Sources: American Heart Association: All About Heart Rate · MedlinePlus: Pulse · ACSM position stand on exercise intensity (2011)

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.