Resting Heart Rate at Night: What’s Normal and What Can Raise It?

If your watch suddenly shows a higher resting heart rate at night, it's easy to worry, but one unusual reading doesn't necessarily mean something is wrong. Heart rate can change with sleep, fitness, stress, alcohol, illness, medicines, hard exercise, poor sleep or dehydration. It's more useful to look at your usual pattern than one number. A lasting change from your normal range is worth paying attention to, especially if it comes with palpitations, dizziness, breathlessness or chest discomfort.

What is a normal resting heart rate at night?

The American Heart Association (AHA) considers about 60 to 100 beats per minute (bpm) typical for most adults when they are awake, calm and at rest, although a lower rate can be normal in physically fit people. It's also worth clarifying the terminology: “resting heart rate” usually refers to a measurement taken while you're awake and resting, while the number recorded during sleep is more accurately described as your sleeping or nocturnal heart rate. During sleep, the National Heart, Lung, and Blood Institute (NHLBI) explains that heart rate generally falls during non-rapid eye movement (NREM) sleep and can rise again during rapid eye movement (REM) sleep or brief awakenings. Cleveland Clinic notes that sleeping heart rate is often around 20% to 30% lower than daytime resting heart rate. So, there isn't one “perfect” overnight number that applies to everyone; age, fitness, medicines and overall health can all influence it.

Why can your heart rate be higher while you sleep?

A higher night does not automatically mean a heart problem. Look first at what changed that day.

Alcohol: Alcohol can have a noticeable effect on your heart rate at night. A randomised crossover study found that alcohol raised nocturnal heart rate and affected sleep quality. Another laboratory study found that drinking alcohol in the evening was linked with a higher heart rate and lower heart rate variability (HRV). A large 2026 real-world study of more than 20,000 people found a similar pattern, with heart rate increasing as alcohol intake went up.

Stress and poor sleep: A stressful day can be carried into the night. Stress triggers the body's fight-or-flight response, and the American Heart Association notes that adrenaline can temporarily raise your heart rate and blood pressure. Poor or broken sleep can also affect your usual overnight pattern. With obstructive sleep apnoea, repeated interruptions in breathing can cause brief awakenings, along with changes in oxygen levels, heart rate and blood pressure. If you snore loudly, gasp for air, have witnessed pauses in breathing, or experience significant daytime sleepiness, it's worth discussing these symptoms with a healthcare professional.

Illness, heat and medicines: Sometimes the reason is fairly simple. A fever, infection, dehydration or even being too warm can push your heart rate up for a while. Medicines can affect it too. Beta blockers can lower heart rate, while some stimulant medicines can raise it. If your heart rate changes around the same time as a new medicine, an illness or another new symptom, that context can tell you more than the number alone.

Does fitness lower resting heart rate?

Often, yes. A systematic review and meta-analysis found that regular exercise can lower resting heart rate, with clearer effects seen with endurance training. But a lower heart rate isn't always better. It can be completely normal in someone who is physically fit and feels well, while certain medicines or heart rhythm problems can also lower it. A tough workout can also temporarily change your overnight readings, so it's better to look at several nights rather than take one unusual reading as a sign of overtraining.

How accurate are smartwatches at night?

Wearables can be useful for spotting changes in your usual pattern, especially when you look at several nights instead of one reading. But they are not equally accurate. A 2025 validation study comparing consumer wearables with an electrocardiogram (ECG) found that accuracy varied between devices for both nocturnal heart rate and heart rate variability (HRV). In general, heart rate tends to be measured more reliably than detailed sleep stages. That makes wearable data useful as a clue, not a diagnosis. The U.S. Food and Drug Administration (FDA) notes that smartwatch cardiovascular alerts can help flag a possible issue, but they are not designed to confirm a medical condition on their own. A repeated change from your usual pattern, especially when it comes with symptoms, matters more than one unusual score.

Look at the pattern, not one bad night

If last night looked unusual, ask:

• Did you drink alcohol?

• Were you ill, feverish or dehydrated?

• Was the day unusually stressful?

• Did you train harder than usual?

• Did you sleep badly or wake repeatedly?

• Did you start or change a medicine?

Change one obvious variable at a time when possible. If everything changes together, it becomes difficult to know what actually affected the number.

When should you worry about your nighttime heart rate?

One unusual wearable reading is rarely enough to show a problem. Arrange medical assessment if your sleeping or resting heart rate stays clearly unusual for you over repeated nights, or if you repeatedly receive irregular-rhythm alerts. A rate below 60 bpm is not automatically abnormal during sleep or in fit people, but a very slow rate with dizziness, weakness, fainting or breathlessness needs assessment. Seek urgent medical care for chest pain, fainting, severe breathlessness or a sustained racing or irregular heartbeat with feeling unwell. Heart-rate changes with loud snoring, gasping or witnessed breathing pauses also deserve medical review.

Related Articles

• Small Healthy Habits for Everyday Wellbeing

• Is Our Food Becoming Less Nutritious? What Science Really Says

Sources

• American Heart Association: All About Heart Rate

• National Heart, Lung, and Blood Institute: Why Is Sleep Important?

• Cleveland Clinic: How Sleep Affects Your Heart Rate

• Pabon E, et al. Effects of alcohol on sleep and nocturnal heart rate. 2022.

• Real-world effects of alcohol on heart rate, sleep and physical activity. 2026.

• Reimers AK, et al. Effects of exercise on resting heart rate: systematic review and meta-analysis.

• Validation of nocturnal resting heart rate and heart rate variability in consumer wearables. 2025.

Medical Disclaimer: This article is for general educational purposes only and should not replace professional medical advice, diagnosis or treatment. Seek medical assessment for persistent or unexplained heart-rate changes, repeated rhythm alerts, breathing pauses during sleep or symptoms such as dizziness, fainting, chest pain or breathlessness. Seek urgent medical care for severe chest pain, fainting, severe breathlessness or a sustained racing or irregular heartbeat with feeling unwell.