A high resting heart rate is anything above 100 beats per minute (bpm) while you’re sitting or lying down and awake. The medical term for this is tachycardia. For adults, the normal range is 60 to 100 bpm, so a consistent reading above that upper boundary signals that something is pushing your heart to work harder than it should at rest.
Normal Ranges by Age
What counts as “normal” depends heavily on age. A newborn’s heart naturally beats much faster than an adult’s, and the range gradually narrows as children grow. Here’s what typical resting rates look like:
- Newborns (birth to 4 weeks): 100 to 205 bpm
- Infants (4 weeks to 1 year): 100 to 180 bpm
- Toddlers (1 to 3 years): 98 to 140 bpm
- Preschool age (3 to 5 years): 80 to 120 bpm
- School age (5 to 12 years): 75 to 118 bpm
- Adolescents (13 to 17 years): 60 to 100 bpm
- Adults (18 and older): 60 to 100 bpm
On the other end of the spectrum, very fit athletes often have resting heart rates closer to 40 bpm. Their hearts pump more blood per beat, so fewer beats are needed. If you’re not a trained athlete and your rate regularly sits below 60 bpm, that’s worth bringing up with a doctor too.
Temporary vs. Persistent Causes
A resting heart rate above 100 doesn’t always mean something is wrong. Plenty of everyday situations spike your pulse temporarily. Stress, anxiety, caffeine, a fever, or just finishing a workout can all push you past 100. Smoking, heavy alcohol use (more than 14 drinks a week for men or 7 for women), and stimulant drugs like cocaine or methamphetamine do the same.
The more concerning scenario is when your resting heart rate stays elevated over weeks or months without an obvious trigger. Several medical conditions can cause this:
- Anemia: When your red blood cell count is low, your heart compensates by beating faster to deliver enough oxygen.
- Overactive thyroid (hyperthyroidism): Excess thyroid hormone speeds up nearly every system in your body, including your heart.
- Electrolyte imbalances: Abnormal levels of potassium, sodium, calcium, or magnesium disrupt the electrical signals that regulate your heartbeat.
- High or low blood pressure: Both extremes force the heart to adjust its rate to maintain circulation.
Medications That Raise Your Heart Rate
Several common medications can nudge your resting heart rate higher, and this catches many people off guard. Inhalers used for asthma (the “rescue” type that opens your airways quickly) stimulate the same receptors that speed up your heart. Decongestants found in cold and sinus medications do the same through a similar pathway.
Certain psychiatric medications, particularly some antipsychotics, can raise heart rate by altering how your nervous system regulates the heart. Steroids prescribed for inflammation occasionally have this effect as well. Even caffeine, technically a stimulant, works by blocking a chemical that normally keeps your heart rate in check. If you’ve noticed your pulse creeping up after starting a new medication, that connection is worth exploring with whoever prescribed it.
Why a Persistently High Rate Matters
A resting heart rate that stays elevated over time is more than an inconvenience. A major long-term study tracked nearly 5,800 people over 25 years and identified four distinct heart rate trajectories. People whose resting heart rate gradually climbed over those decades, whether the increase was slight or dramatic, were 65% more likely to develop heart failure than those whose rate stayed stable or declined slightly. They were also 69% more likely to die from any cause during the study period. These numbers held even after researchers accounted for other cardiovascular risk factors like blood pressure and cholesterol.
The takeaway isn’t that a single high reading predicts disaster. It’s that your resting heart rate over time tells a story about your cardiovascular fitness and overall health. A rate that trends upward year after year may be an early signal that something is changing, often before other symptoms appear.
How to Measure Your Resting Heart Rate Accurately
Getting an accurate reading requires a little more care than just checking your pulse whenever you think of it. The most reliable approach is to measure after you’ve been sitting calmly for several minutes, ideally in the morning before you’ve had coffee or done anything strenuous.
A few specific guidelines help avoid misleading numbers. Don’t measure within one to two hours after exercise, because your heart rate stays elevated well after you stop moving. Wait at least an hour after drinking caffeine. And avoid taking a reading right after you’ve been standing or sitting for a very long time, since both can temporarily shift your rate. Place two fingers (index and middle) on the inside of your wrist just below the base of your thumb, count the beats for 30 seconds, and double the number. Doing this a few times a week gives you a much clearer picture than a single snapshot.
Warning Signs Alongside a Fast Heart Rate
A resting heart rate above 100 on its own may be harmless if it’s situational. But certain accompanying symptoms suggest your heart isn’t just beating fast; it’s struggling. Palpitations (the sensation that your heart is pounding, fluttering, or skipping), shortness of breath, chest pain, and dizziness are the key red flags. If your heart rate is above 100 and you’re experiencing any of these, that combination warrants immediate medical attention. The same applies if your rate drops below 35 to 40 bpm with similar symptoms.