Why is my resting heart rate going up?

Your resting heart rate usually goes up for a short-term reason: an infection coming on, alcohol the night before, short sleep, the second half of the menstrual cycle, or a stressful week. Longer rises can come from pregnancy, medicines or a thyroid problem. A rise of 5 to 10 bpm for a few days often has a simple cause you can find in your last week.

The table below lists the common causes with the size of the effect where studies measured it. Then work through the checklist. If the rise stays without a cause, or comes with symptoms, see a doctor. For normal values by age and sex, see the resting heart rate by age chart.

How much does resting heart rate normally change?

Resting heart rate changes a little from week to week even in healthy people. In wearable data from 92,457 adults, the typical week-to-week change for one person was about 3 bpm. About 20% of people had at least one week where their resting heart rate moved by 10 bpm or more. So a 2 to 3 bpm rise is usually noise.

What separates noise from a signal is size and duration. One high morning after a late night means little. Several days in a row clearly above your usual range, with no change in watch fit, is a pattern. Compare with your own baseline, not with a population chart.

What are the common causes of a rising resting heart rate?

The common causes are infection and fever, alcohol, short sleep, the luteal phase of the menstrual cycle, pregnancy, season, stress, medicines and high elevation. Some act overnight, others over weeks. Thyroid overactivity and heart rhythm problems are less common but are reasons to see a doctor if the rise persists.

Cause	Typical effect on resting heart rate	Time course
Fever, acute infection	About 8.5 bpm higher per 1 °C of fever	Days, can start before symptoms
Alcohol in the evening	+1.4, +4.0 and +8.7 bpm during sleep after low, moderate and high intake	Same night
Sleep length	Lowest resting heart rate at about 7 to 7.5 hours of sleep	Days
Luteal phase (after ovulation)	Higher than in the first half of the cycle	About 2 weeks each cycle
Pregnancy	Average rises from about 79 to 87 bpm between week 10 and week 40	Months
Season	About 2 bpm higher in early January than late July (population average)	Months
Stress, travel	Can trigger heart-rate-based alerts in wearable studies	Days
Medicines, high elevation	Listed by Apple as possible causes of out-of-range overnight vitals	Varies
Overactive thyroid	"Rapid and irregular heartbeat" is a listed symptom	Weeks to months

Sources: Karjalainen and Viitasalo 1986; Pietilä et al. 2018; Quer et al. 2020; Goodale et al. 2019; Loerup et al. 2019; Alavi et al. 2022; Apple Support; MedlinePlus.

Could I be getting sick?

Yes, an infection is one of the most common reasons for a sudden rise. Fever raises heart rate by about 8.5 bpm for each 1 °C, and in one study the rate stayed high even during sleep. Wearable studies have found resting heart rate rises before or at symptom onset in many infections, so the number can move days before you feel ill.

In a Stanford study of 3,318 people, a smartwatch alerting system based on heart rate and steps flagged 80% of COVID-19 infections, with signals a median of 3 days before symptoms. The same system also triggered on stress, alcohol and travel, but less often. That is why a single high reading is a prompt to check, not a diagnosis. Details are in heart rate when sick.

Did I drink alcohol or sleep badly?

Alcohol and short sleep are the most common causes of a single high morning. In 4,098 adults, sleeping heart rate rose 1.4 bpm after low intake, 4.0 bpm after moderate and 8.7 bpm after high intake. In wearable data, resting heart rate was lowest in people who averaged 7 to 7.5 hours of sleep.

Check the last 3 nights: drinks, late meals, bedtime and total sleep. If your rise lines up with them and falls back within a day or two, you have found the cause. The sleeping heart rate guide explains how the overnight curve shows this.

Is it my menstrual cycle or pregnancy?

Hormones can raise resting heart rate for weeks. Wearable studies have measured higher resting pulse in the luteal phase, after ovulation, than in the first half of the cycle. In pregnancy, a meta-analysis of 8,317 women found average heart rate rose from about 79 bpm at 10 weeks to about 87 bpm at 40 weeks.

If you track your cycle, compare this month with the same phase in earlier months. A rise that appears every month after ovulation and falls with your period is a normal pattern. A rise in early pregnancy is also expected; your prenatal care team can tell you what is normal for you.

Have I been training hard or stopped training?

Training is linked with resting heart rate. Regular endurance exercise and yoga are associated with a lower resting heart rate over weeks to months, so a long break from training can remove part of that effect. A rise that follows an unusually heavy week is a reason to look at your recovery before you add more load.

If your resting heart rate is up after a heavy week and your HRV is down, check your training load. The overtraining symptoms guide covers the warning signs your data shows first, and how to lower your resting heart rate covers what tends to bring the baseline back down.

Could it be the device?

Sometimes the rise is in the measurement, not in you. A loose watch band, a new device, a new strap position or a change of app can shift resting heart rate values. Apple notes that if the watch is too loose, its sensors might not capture accurate readings. A new method needs its own baseline.

• Fit: Wear the watch snug, especially at night.
• Device change: Treat the first 1 to 2 weeks on a new device as a new baseline.
• Method change: Clinic pulse, watch overnight value and phone camera reading are different measurements. Do not compare across them.

When should you see a doctor about a rising resting heart rate?

See a doctor if your resting heart rate stays above 100 bpm, if a rise lasts more than a few days without a clear cause, or if it comes with palpitations, an irregular pulse, dizziness, fainting, chest pain, shortness of breath or unexplained weight loss. Get emergency care for severe symptoms.

Bring your trend. A chart of daily resting heart rate, with notes on sleep, alcohol, illness and cycle, is more useful to a doctor than a single number. A wearable or app can show that something changed. It can not say why, and it can not diagnose a rhythm or thyroid problem.

How Svanu spots a rise against your own baseline

Svanu reads resting heart rate from Apple Health, or derives it from heart-rate samples as the lowest 30-minute average during your main sleep when your watch does not write one. Derived values are only compared with derived values.

Illness detection compares your resting heart rate, HRV, wrist temperature, blood oxygen and respiratory rate with your own recent baseline, using prior days only. It flags a change only when it is both statistically unusual and large enough. It is a wellness signal, never a diagnosis. The recovery score uses the same resting heart rate, and each score shows its inputs and what moved it, so you can see if alcohol, sleep or a possible illness is behind a high morning. Read more about illness detection and recovery in Svanu.