A normal resting heart rate for adults falls between 60 and 100 beats per minute (bpm). That range applies whether you’re 18 or 80, though where you personally land within it depends on your fitness level, medications, and what’s happening in your body at that moment. Your heart rate also shifts significantly during sleep, exercise, and stress, so “how fast should your heart beat” really has several answers depending on what you’re doing.
Resting Heart Rate by Age
Children’s hearts beat considerably faster than adults’. A newborn’s resting heart rate can be anywhere from 100 to 205 bpm, which would be alarming in an adult but is completely normal for a baby. As children grow, their hearts get larger and more efficient, and the rate gradually slows:
- Newborn to 4 weeks: 100 to 205 bpm
- 1 month to 1 year: 100 to 180 bpm
- 1 to 3 years: 98 to 140 bpm
- 3 to 5 years: 80 to 120 bpm
- 5 to 12 years: 75 to 118 bpm
- 13 to 17 years: 60 to 100 bpm
- Adults (18+): 60 to 100 bpm
By the teenage years, heart rate settles into the adult range and stays there for the rest of your life. These numbers are for someone who is awake, calm, and sitting or lying down. Standing up, walking around the house, or even digesting a meal can push your rate a bit higher without anything being wrong.
What Your Heart Rate Should Be During Sleep
Your heart rate drops about 20% to 30% below your daytime resting rate while you sleep. For most healthy adults, that puts the sleeping range somewhere around 50 to 75 bpm. During the deepest stages of sleep, your rate reaches its lowest point of the day, and it’s normal to see numbers in the low 50s or even high 40s on a wearable tracker overnight.
If you notice your sleeping heart rate is consistently above your daytime resting rate, or it spikes for no clear reason during the night, that’s worth paying attention to. Alcohol, illness, and sleep apnea can all keep your heart working harder than it should while you’re asleep.
Target Heart Rate During Exercise
During a workout, you want your heart rate to climb well above the resting range. The American Heart Association defines two main exercise zones based on your estimated maximum heart rate:
- Moderate intensity: 50% to 70% of your maximum heart rate. This is a brisk walk, easy bike ride, or casual swim.
- Vigorous intensity: 70% to 85% of your maximum heart rate. This is running, fast cycling, or high-intensity interval training.
The simplest way to estimate your maximum heart rate is 220 minus your age. A 40-year-old would have an estimated max of 180 bpm, putting their moderate exercise zone at roughly 90 to 126 bpm and their vigorous zone at 126 to 153 bpm. That formula is a rough estimate, though. Researchers at the Norwegian University of Science and Technology found it can underestimate maximum heart rate by up to 40 beats per minute in older adults. Their updated formula, 211 minus 0.64 times your age, tends to be more accurate, especially past age 40.
Here are the American Heart Association’s target exercise zones by decade:
- Age 20: 100 to 170 bpm (max ~200)
- Age 30: 95 to 162 bpm (max ~190)
- Age 40: 90 to 153 bpm (max ~180)
- Age 50: 85 to 145 bpm (max ~170)
- Age 60: 80 to 136 bpm (max ~160)
- Age 70: 75 to 128 bpm (max ~150)
Serious symptoms during exercise are uncommon as long as your heart rate stays below about 150 bpm, assuming you have a healthy heart. Going above your target zone briefly isn’t dangerous for most people, but consistently training above 85% of your max increases injury risk without adding much fitness benefit.
Why Some People Have a Lower Resting Rate
A resting heart rate below 60 bpm isn’t automatically a problem. Endurance athletes frequently have resting rates in the 40s or 50s because their hearts have physically adapted to regular training. Sustained cardiovascular exercise increases the heart’s size and the strength of each contraction, so it pumps more blood per beat and doesn’t need to beat as often. The nervous system also shifts, with the calming branch becoming more active at rest.
You don’t need to be an elite athlete for this to happen. People who walk, swim, or cycle regularly for several months often see their resting heart rate drop by 5 to 10 bpm. A lower resting rate within a healthy range is generally a sign of good cardiovascular fitness. However, if your heart rate drops below 60 and you feel dizzy, fatigued, or short of breath, that’s a different situation. Clinically, a heart rate below 60 bpm is called bradycardia, and it only requires attention when it causes symptoms.
When a Heart Rate Is Too Fast or Too Slow
A resting heart rate above 100 bpm in an adult is called tachycardia. It’s normal during exercise, anxiety, or illness, but if your resting rate stays above 100 without an obvious explanation, something may be driving it: thyroid problems, anemia, infection, or a heart rhythm disorder. Rates above 120 bpm at rest more likely point to an abnormal rhythm rather than the heart simply beating faster in its normal pattern.
On the slow end, bradycardia (below 60 bpm) is common and harmless in fit individuals. It becomes a concern when it causes lightheadedness, fainting, extreme fatigue, or confusion. Some people naturally run in the mid-50s their entire lives with no issues at all.
The context matters more than the number. A heart rate of 110 bpm after climbing stairs is completely normal. The same rate while sitting on the couch watching television is not.
What Can Change Your Heart Rate
Several everyday factors push your heart rate up or down, sometimes by more than you’d expect.
Caffeine triggers the release of stress hormones that can increase heart rate and blood pressure in some people. Interestingly, regular coffee drinkers often develop a tolerance and don’t see much of an effect. People who are sensitive to caffeine, or who already have a tendency toward irregular heart rhythms, are more likely to notice their heart speeding up after a cup.
Dehydration forces your heart to work harder because there’s less blood volume circulating, so your heart compensates by beating faster. Even mild dehydration from skipping water on a hot day can raise your resting rate by 10 to 20 bpm.
Medications have a major impact. Beta-blockers, commonly prescribed for high blood pressure, slow the heart rate and can prevent you from reaching your normal target zone during exercise, no matter how hard you push. If you take a beta-blocker, using perceived effort rather than a heart rate number is a more reliable way to gauge exercise intensity. On the other end, stimulant medications for ADHD and decongestants like pseudoephedrine tend to raise resting heart rate.
Stress, fever, pain, and poor sleep all raise heart rate too. A temporary spike is your body’s normal response. A sustained elevation over days or weeks, especially when you can’t identify the cause, is worth investigating.
How to Check Your Heart Rate Accurately
Place two fingers (index and middle, not your thumb) on the inside of your wrist just below the base of your thumb. Count the beats for 30 seconds and multiply by two. For the most accurate resting reading, do this first thing in the morning before getting out of bed, or after sitting quietly for at least five minutes.
Wrist-based fitness trackers and smartwatches are reasonably accurate for resting and sleeping heart rate, though they can be less reliable during high-intensity exercise when your wrist is sweating and moving. Chest strap monitors remain the most accurate option during workouts if precise numbers matter to you.
Tracking your resting heart rate over weeks gives you more useful information than any single reading. A gradual downward trend usually reflects improving fitness. A sudden jump of 10 or more bpm that lasts several days can be an early sign of illness, overtraining, or stress before you notice other symptoms.