Heart rate 148 on an adult - what does it mean?

Where 148 bpm sits on the adult scale

What a resting pulse of 148 means

If you just climbed stairs, exercised or are very anxious, a pulse of 148 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 148 bpm the heart beats about every 0.41 seconds — roughly 213,120 beats a day.

When anemia is severe enough to push the heart to 148

In mild anemia the heart adds a few beats and most people barely notice. As hemoglobin falls further, the heart has to work harder and harder to deliver the same oxygen. Each beat carries less, so the body asks for more beats and more blood with each one. When this reserve is used up, the pulse stays high even at rest. A resting rate of 148 with known or suspected anemia means the heart is at the edge of what it can make up for.

For comparison, hemoglobin in healthy adults is roughly 12 to 15.5 g/dL in women and 13.5 to 17.5 g/dL in men, though labs differ slightly. People can adjust surprisingly well to a slow fall over months. A fast drop, such as from bleeding, leaves the body no time to adapt and causes symptoms at much higher levels.

Signs that the heart is under strain

• breathless while sitting or talking, not only on stairs;
• chest pain or pressure, especially in people with narrowed heart arteries, because the heart muscle itself is short of oxygen;
• feeling faint, or blacking out when standing up;
• swollen ankles and lying flat becoming uncomfortable;
• very pale or yellowish skin, or confusion in older adults.

Any of these with a pulse this fast is a reason to go to the emergency room or call 911. Anyone with known heart disease is less able to cope with a low blood count and should not wait.

How severe anemia is treated

In hospital, the first steps are a blood count, a search for bleeding and tests for the cause. A blood transfusion can raise hemoglobin within hours. For stable patients, many hospitals consider transfusion when hemoglobin is below about 7 g/dL, with a higher threshold for people with heart disease or ongoing bleeding. Iron can also be given straight into a vein, which works faster than tablets, and vitamin B12 can be given by injection.

Once red cells are restored, the heart can slow down again. The pulse is a useful sign of progress. Expect it to come down over days after a transfusion and over weeks with iron or vitamins alone. Avoid strenuous exercise until your doctor confirms your blood count has recovered.

If you have been told your anemia is mild and see a resting 148, do not assume it is the same problem. Rest, re-measure and seek care today if it stays high. Our normal adult heart rate page shows how far 148 is from the usual range.

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

• 143 bpm
• 144 bpm
• 145 bpm
• 146 bpm
• 147 bpm
• 149 bpm
• 150 bpm
• 151 bpm
• 152 bpm
• 153 bpm

Measured on a child instead? See heart rate 148 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.