Normal Sleeping Heart Rate: Healthy Ranges, Causes of Changes, and How to Improve It

Why Your Sleeping Heart Rate Matters

You probably don’t think much about your heart rate while you’re asleep. After all, you’re not running, exercising, or even moving much. But your heart is still working non-stop, and the way it behaves during sleep can tell you a surprising amount about your overall health.

Your sleeping heart rate — the number of times your heart beats per minute while you’re asleep — isn’t random. It follows predictable patterns based on your body’s needs, your sleep stages, and your overall health. In fact, significant changes in your sleeping heart rate can sometimes be an early sign of stress, illness, or cardiovascular problems.

Understanding what’s normal for you can help you catch potential problems early, improve your sleep quality, and even support better heart health over time.

What Is a Normal Sleeping Heart Rate?

In healthy adults, a normal sleeping heart rate generally falls between 40 and 60 beats per minute (bpm) if you’re physically fit, and between 60 and 100 bpm for most people. That’s a bit lower than the typical resting heart rate when you’re awake, which is usually between 60 and 100 bpm.

This drop in heart rate happens because your body is in a relaxed state during sleep. Your muscles are resting, your breathing slows down, and your heart doesn’t have to work as hard to pump blood.

However, what’s “normal” can vary widely depending on your age, fitness level, and other health factors. For example, an endurance athlete might have a sleeping heart rate in the low 40s without any problems, while an older adult might naturally have a slightly higher sleeping heart rate due to changes in the cardiovascular system.

Normal Sleeping Heart Rate by Age

Your age plays a big role in determining your sleeping heart rate. Babies and children tend to have much faster heart rates than adults because their hearts are smaller and their metabolism is faster.

• Newborns (0–3 months) often have a sleeping heart rate of 100–150 bpm.
• Infants (3–12 months) usually range between 90 and 140 bpm.
• Toddlers and young children often have sleeping heart rates between 80 and 120 bpm.
• Teens typically fall between 60 and 100 bpm.
• Adults average between 40 and 100 bpm depending on fitness and health.
• Older adults may have slightly higher rates due to reduced heart efficiency.

These ranges are general guidelines, not strict cut-offs. What matters more is whether your heart rate during sleep is consistent for you and whether sudden changes occur without explanation.

Why Your Heart Rate Changes While You Sleep

Your sleeping heart rate isn’t a flat, steady number. It changes throughout the night as your body moves through different sleep stages — light sleep, deep sleep, and rapid eye movement (REM) sleep.

During non-REM sleep (light and deep stages), your body is in repair mode. Your breathing slows, blood pressure drops, and your heart rate falls to its lowest point of the night. This is when your heart gets a real break, and it’s one reason good deep sleep is important for heart health.

During REM sleep, however, your brain becomes more active, your breathing quickens slightly, and your heart rate can temporarily rise. This is the stage where you dream, and sometimes your heart may even speed up during particularly vivid or intense dreams.

These fluctuations are normal and healthy. Problems usually arise only when your heart rate remains consistently too high or too low throughout the night.

Factors That Affect Sleeping Heart Rate

Many things can influence your heart rate while you sleep. Some are completely normal, while others might signal a need for lifestyle changes or medical attention.

Your fitness level plays one of the biggest roles. If you’re physically active and have good cardiovascular health, your heart muscle is stronger and more efficient. It can pump blood with fewer beats, leading to a naturally lower sleeping heart rate. On the other hand, if you’re less active, your heart may need to work harder, even during rest.

Stress and anxiety can keep your nervous system on high alert, preventing your heart rate from dropping as much as it should. Even if you’re asleep, your body might still act as though it’s in “fight or flight” mode.

Illness or fever can raise your heart rate temporarily, as can dehydration. Alcohol, caffeine, and heavy meals late at night can also keep your heart rate elevated.

Certain medical conditions like hyperthyroidism, anemia, heart disease, and sleep apnea can significantly affect your sleeping heart rate. Sleep apnea in particular can cause sharp spikes and drops in heart rate throughout the night due to pauses in breathing.

RELATED READ: Does Blood Sugar Affect Heart Rate? The Connection Explained

When to Worry About Sleeping Heart Rate

It’s normal for your sleeping heart rate to fluctuate, but there are situations where it’s worth getting checked out.

If your heart rate is consistently above 100 bpm during sleep without any obvious cause — and especially if you experience symptoms like shortness of breath, chest pain, or dizziness — it may indicate tachycardia, an abnormally fast heart rhythm.

On the other end of the spectrum, a sleeping heart rate consistently below 40 bpm could be bradycardia. This is not necessarily dangerous if you’re an athlete, but if you also feel weak, dizzy, or faint, it could be a sign of a heart conduction problem.

The most important thing is to pay attention to changes over time. If your normal sleeping heart rate suddenly increases or decreases and stays that way, it’s a good idea to consult a doctor.

How to Measure Your Sleeping Heart Rate

Thanks to modern technology, it’s easier than ever to check your heart rate while you sleep. Wearable fitness trackers like the Apple Watch, Fitbit, or Garmin devices can monitor your heart rate continuously throughout the night. These are generally accurate for spotting trends, though they may not be perfect to the beat.

For more precise measurements, medical-grade chest straps or home ECG devices can be used. In some cases, your doctor may recommend an overnight sleep study, which can track your heart rate along with breathing patterns, oxygen levels, and brain activity.

Even without technology, you can get a rough idea by checking your pulse right after waking up in the middle of the night or first thing in the morning before getting out of bed.

How to Maintain a Healthy Sleeping Heart Rate

Improving your sleeping heart rate usually comes down to supporting your overall cardiovascular health and creating good sleep habits.

Regular exercise is one of the best ways to strengthen your heart so it beats more efficiently, even at rest. Aerobic activities like walking, cycling, and swimming are especially beneficial.

Stress management is equally important. Practicing relaxation techniques such as deep breathing, meditation, or gentle stretching before bed can help your heart rate drop more easily.

Your sleep environment matters too. A cool, dark, and quiet bedroom supports better rest, allowing your heart rate to follow its natural nightly rhythm.

Finally, avoid late-night stimulants like caffeine, large meals, and alcohol. Staying hydrated during the day also helps prevent unnecessary increases in heart rate at night.

Special Cases: Sleeping Heart Rate in Certain Groups

Pregnant women often experience a slightly higher sleeping heart rate because the body is pumping more blood to support the growing baby. This is usually normal but should be monitored if accompanied by symptoms like dizziness or chest discomfort.

Athletes, on the other hand, often have very low sleeping heart rates — sometimes in the low 40s or even high 30s — simply because their hearts are so efficient.

For people with diagnosed heart conditions, keeping track of sleeping heart rate can help detect changes that might require medical intervention.

Frequently Asked Questions

1. Why is my sleeping heart rate higher than my resting heart rate during the day?

This can happen if you go to bed stressed, eat a large meal right before sleep, or consume alcohol or caffeine in the evening. Illness, dehydration, or underlying sleep disorders like sleep apnea can also keep your heart rate elevated at night. If it’s persistent, you may want to track it and speak to a healthcare provider.

2. Can dehydration cause a high sleeping heart rate?

Yes. When you’re dehydrated, your blood volume decreases, which makes your heart work harder to pump oxygen to your body. This can keep your heart rate higher, even while you’re sleeping.

3. Why does my heart rate drop suddenly during sleep?

A sudden drop can be a normal part of deep sleep when the body is most relaxed. However, in some cases — such as severe sleep apnea or heart rhythm disorders — abrupt drops may be linked to pauses in breathing or heart conduction issues. If drops are extreme or you have symptoms like dizziness or fainting during the day, seek medical advice.

4. Does sleeping on your left side affect heart rate?

For most people, sleeping position has little effect on heart rate. However, people with certain heart conditions may find that lying on the left side makes them more aware of their heartbeat. This is usually harmless but can feel uncomfortable.

5. Is a sleeping heart rate of 120 bpm dangerous?

A heart rate consistently above 100 bpm during sleep is generally considered higher than normal and could indicate stress, fever, infection, hyperthyroidism, anemia, or heart rhythm problems. If your heart rate stays this high at night, it’s important to get checked by a doctor.

6. Can poor air quality in the bedroom raise my sleeping heart rate?

Yes. Low oxygen levels from poor ventilation, high altitude, or pollution can make your heart beat faster to compensate for less oxygen in the blood. Using an air purifier or improving airflow may help.

7. Why is my sleeping heart rate lower after intense exercise?

After consistent endurance training, your heart becomes more efficient, meaning it can pump the same amount of blood with fewer beats. This “training effect” often results in a lower sleeping heart rate.

8. Do hormones affect sleeping heart rate?

Absolutely. Hormonal changes during pregnancy, menopause, or menstrual cycles can temporarily raise or lower heart rate. Thyroid hormones, in particular, have a strong effect — overactive thyroid speeds it up, underactive slows it down.

9. Can low blood sugar at night affect heart rate?

Yes. Low blood sugar can trigger the release of stress hormones like adrenaline, which may cause your heart rate to spike, sometimes waking you up in the process.

10. What’s the best way to track sleeping heart rate trends over time?

Use a wearable device consistently under the same conditions (same position, similar bedtime, and similar lifestyle habits). Review the average weekly or monthly data rather than focusing on one night, as trends are more important than single readings.

Final Thoughts

Your sleeping heart rate is more than just a number — it’s a window into your cardiovascular health, stress levels, and even sleep quality. While there’s no single “perfect” number for everyone, knowing your usual range and watching for changes can help you stay ahead of potential problems.

By keeping your heart healthy through regular exercise, managing stress, and getting good-quality sleep, you can support both your nightly rest and your long-term well-being.