Is a Resting Heart Rate of 55 Good?

What a resting heart rate of 55 usually means

Your resting heart rate is how often your heart beats while you are calm, seated or lying down, and have not just been active. The widely quoted normal range of 60 to 100 BPM comes from population averages, not from a line between healthy and unhealthy. Plenty of healthy adults sit in the 50s.

A rate of 55 most often reflects one of these:

• Fitness. Aerobic training enlarges the heart’s left ventricle slightly and strengthens it, so each beat pumps more blood. Fewer beats are needed at rest. Recreational runners, cyclists and swimmers commonly rest between 48 and 58.
• Good recovery. After a full night’s sleep and before caffeine, the parasympathetic nervous system dominates and slows the heart. The same person may read 55 at 7 a.m. and 68 at 3 p.m.
• Genetics. Some people simply run slow, with no training history and no symptoms.
• Medication. Beta blockers, some blood pressure drugs and some heart rhythm medicines lower resting heart rate by design.

Resting heart rate of 55 by age

Adult resting heart rate changes little with age. What changes is how the number is interpreted against fitness.

Age	55 BPM is…
18 to 35	Typical for someone active, slightly low for someone sedentary
36 to 55	A good sign; in the “excellent” band for most fitness charts
56 and over	Fine if long-standing and symptom-free; worth mentioning to a doctor if new

For children the picture is different. Resting rates below 60 are unusual under about age 10 and should be checked.

When 55 is not fine

Bradycardia is the medical term for a resting heart rate under 60. It only matters when the heart is not meeting the body’s needs. Pay attention if 55 comes with any of the following:

• Dizziness or light-headedness, especially when standing up
• Fainting or near-fainting
• Unusual tiredness or trouble exercising at your normal level
• Shortness of breath at rest or with mild effort
• Chest discomfort
• Confusion or trouble concentrating

Also take note if 55 is a change. If you have rested at 70 for years and now read 55 without any change in training, that trend deserves a conversation with your doctor, even without symptoms. Thyroid problems, electrolyte imbalances, sleep apnoea and conduction problems in the heart can all lower heart rate.

How to check whether your 55 is accurate

A single reading can mislead. Caffeine, talking, a cold room, or measuring right after sitting down all shift the number.

1. Measure in the morning, before coffee, after sitting quietly for five minutes.
2. Use the same method each time. With Pulse Tracker, place your fingertip on the iPhone camera and hold still for 30 seconds; the app shows the pulse wave and a quality score so you know the reading is clean.
3. Repeat for a week and look at the average, not one value.
4. Note anything unusual, such as a late night or a hard workout the day before. The app saves mood and notes with each reading for exactly this reason.

If your weekly average is 55, you feel well, and the trend is stable, you have your answer: it is a good resting heart rate.

What to do with the number

Nothing, if you feel fine. If you want to use it, track it alongside heart rate variability. A resting rate of 55 with healthy HRV for your age points to a well-recovered nervous system. A rate of 55 with unusually low HRV, in someone who is not an athlete, is a reason to look at sleep, stress and alcohol before anything else.

Sources

• American Heart Association, All About Heart Rate (Pulse)
• Mayo Clinic, Bradycardia: Symptoms and causes
• Zhang D, Shen X, Qi X. Resting heart rate and all-cause and cardiovascular mortality in the general population: a meta-analysis. CMAJ, 2016.

Related: Normal resting heart rate by age · What is HRV and what is a good number? · How to measure heart rate on iPhone

Wellness disclaimer. Pulse Tracker is intended for general wellness use only. It is not a medical device, is not FDA cleared or approved, and is not intended to diagnose, treat, cure or prevent any disease or condition. Blood pressure shown in the app is either a value you entered from your own cuff or an estimate derived from the pulse signal after cuff calibration; it is not a measurement and must not be used to make medical decisions. Read the full wellness disclaimer. Camera readings, estimates and classifications are for general information only and can be affected by movement, lighting, skin temperature and other factors. Do not use them to diagnose, treat or make decisions about a medical condition. Always consult a qualified healthcare professional, and call emergency services if you have chest pain, shortness of breath, fainting or other urgent symptoms.