Heart rate 55 on an adult - what does it mean?

Where 55 bpm sits on the adult scale

What a resting pulse of 55 means

A pulse in the 50s at rest is typical for people who exercise regularly, and for most adults first thing in the morning. Large population studies associate lower resting heart rates — within the normal range — with better cardiovascular fitness.

It matters only if it comes with symptoms such as unusual tiredness, dizziness, shortness of breath or fainting, or if it is a new change for you without a training explanation.

Ranges apply to adults and children aged 10 and older, measured at rest (American Heart Association). By the numbers: at 55 bpm the heart beats about every 1.09 seconds — roughly 79,200 beats a day.

Your pulse used to be higher, and now it reads 55

A resting 55 is often a sign of good health. But a number tells only half the story. Someone whose usual morning pulse has been 55 for ten years is in a very different position from someone who sat at 72 last spring and now sees 55 without any change in habits. When a low-50s rate is new, the most useful question is simply: what changed?

Start by checking that the drop is real. Compare readings taken the same way, at the same time of day and in the same position, over at least a week. If the average has genuinely fallen by ten beats or more, the change deserves an explanation.

Most answers turn out to be ordinary. Working through them in order helps you and your doctor find the likely cause quickly.

A checklist of common reasons for a new drop

• More exercise. Several months of regular walking, cycling or running lower the resting rate. This is the most welcome explanation.
• A new or changed medicine. Beta blockers, verapamil, diltiazem, digoxin, some antiarrhythmics and beta-blocker eye drops for glaucoma all slow the heart. Check whether a dose was raised recently.
• A new device. Switching from a cuff to a watch, or from one watch to another, can shift the reported number by a few beats.
• A different measuring time. Readings taken lying in bed in the morning are lower than those taken seated at noon.
• Thyroid changes. An underactive thyroid slows metabolism and the pulse, often with weight gain, feeling cold, dry skin and constipation.
• Sleep apnea. Loud snoring, pauses in breathing and daytime sleepiness are clues.
• The heart’s wiring. Age-related changes in the sinus node or AV node can slow the rate gradually.

Deciding what to do

If exercise explains the change and you feel well, nothing needs to be done. If you cannot find an obvious reason, note how the drop happened, whether over weeks or overnight, and mention it at your next check-up. A doctor will usually start with an ECG and a blood test for thyroid function.

Book sooner if the new 55 comes with tiredness, dizziness, shortness of breath on light effort or reduced exercise tolerance, and get urgent help for fainting or chest pain. Comparing yourself with your own past readings matters more than comparing with averages, as the guide to normal adult heart rate explains.

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

• 50 bpm
• 51 bpm
• 52 bpm
• 53 bpm
• 54 bpm
• 56 bpm
• 57 bpm
• 58 bpm
• 59 bpm
• 60 bpm

Measured on a child instead? See heart rate 55 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.