Whether 150 bpm is high depends entirely on what you’re doing when your heart hits that number. At rest, 150 bpm is well above normal and qualifies as tachycardia, a medical term for any resting heart rate over 100 bpm. During exercise, 150 bpm is perfectly normal for most adults under 65 and falls squarely within recommended training zones. For infants and toddlers, 150 bpm can be completely routine even during sleep.
150 BPM at Rest Is Too High
A normal resting heart rate for adults and children over 10 sits between 60 and 100 bpm. At 150 bpm, your heart is beating 50% faster than the upper limit of that range. That’s significant. A heart rate this elevated while sitting or lying down usually means something is driving it up, whether that’s a temporary trigger like stress or dehydration, or a medical issue that needs attention.
Common causes of a resting heart rate near 150 bpm include dehydration, fever, anemia, low blood sugar, high blood pressure, pregnancy, and untreated thyroid problems. Chronic high caffeine intake (400 mg or more daily, roughly four or more cups of coffee) raises resting heart rate and blood pressure over time, according to research published by the American College of Cardiology. Nicotine has a similar stimulating effect. Anxiety and panic attacks can also push your heart rate into this territory temporarily.
In some cases, a resting rate around 150 bpm points to a heart rhythm problem. Supraventricular tachycardia (SVT) is one of the more common culprits. It starts in the upper chambers of the heart and can cause sudden episodes where your heart races at 150 bpm or higher, then drops back to normal. Atrial fibrillation, another rhythm disorder, can also produce rates in this range.
150 BPM During Exercise
During a workout, 150 bpm is well within the safe zone for most adults. Your estimated maximum heart rate is roughly 220 minus your age, and the American Heart Association recommends exercising at 50 to 85% of that number. Here’s how 150 bpm fits in at different ages:
- Age 20: Target zone is 100 to 170 bpm. A rate of 150 is 75% of your max, solidly in the vigorous range.
- Age 30: Target zone is 95 to 162 bpm. Still well within range at about 79% of max.
- Age 40: Target zone is 90 to 153 bpm. You’re near the top of the zone at 83% of max.
- Age 50: Target zone is 85 to 145 bpm. At 150, you’ve just exceeded the recommended ceiling and are pushing close to 88% of your estimated max.
- Age 60: Target zone is 80 to 136 bpm. A rate of 150 is 94% of your estimated maximum, which means you’re straining.
- Age 70: 150 bpm is your estimated maximum heart rate. You should not be sustaining this during exercise.
If you’re in your 20s or 30s, hitting 150 bpm during a run or cycling session is completely expected during vigorous effort. If you’re over 50, that same number suggests you should ease up. These formulas are averages, not exact thresholds for every individual, but they’re useful guides for spotting when you’re working harder than intended.
150 BPM in Babies and Young Children
Children’s hearts beat much faster than adults’. A newborn’s normal awake heart rate ranges from 85 to 205 bpm, and even during sleep it can reach 160 bpm. For babies aged 3 months to 2 years, the awake range is 100 to 190 bpm. So 150 bpm in an infant is entirely normal and not a cause for concern on its own. By the time a child reaches age 10, the normal range narrows to the adult standard of 60 to 100 bpm.
Warning Signs That Need Immediate Attention
A sustained resting heart rate of 150 bpm paired with certain symptoms is a medical emergency. The Mayo Clinic identifies these red flags: chest pain or discomfort, shortness of breath, dizziness or lightheadedness, and weakness. If your heart is racing and you experience any of these, get emergency help.
The most dangerous scenario is ventricular fibrillation, where the lower chambers of the heart quiver chaotically instead of pumping blood. Blood pressure drops, breathing stops, and the heart effectively ceases functioning. This is cardiac arrest and requires immediate intervention.
A single brief spike to 150 bpm from standing up quickly, a scare, or a burst of activity is generally harmless. What matters is the context: how long it lasts, what you’re doing, whether it keeps happening, and whether you feel symptoms alongside it.
How to Check Your Heart Rate Accurately
If you’re relying on a smartwatch or fitness tracker, it’s worth verifying with a manual check. Place the tips of your index and middle fingers on the inside of your wrist, between the wrist bone and the tendon on the thumb side. You should feel a steady pulse. Count the beats for a full 60 seconds for the most accurate reading. A quicker method is counting for 15 seconds and multiplying by four, though this is slightly less precise.
You can also check your pulse at your neck by placing two fingers in the groove next to your windpipe on one side. Avoid pressing too hard, which can slow the pulse and give you an inaccurate count. For resting heart rate, sit quietly for at least five minutes before measuring. First thing in the morning, before getting out of bed, gives you the most consistent baseline number.
What Brings a High Resting Heart Rate Down
If your resting heart rate runs high but you don’t have an underlying rhythm disorder, the most effective fix is regular aerobic exercise. Over weeks and months, consistent cardio strengthens the heart muscle so it pumps more blood per beat, reducing how often it needs to beat at rest. Many trained endurance athletes have resting heart rates in the 40s and 50s.
In the short term, reducing caffeine intake, staying well hydrated, managing stress, and getting adequate sleep all help. If your heart rate frequently sits above 100 bpm at rest, or you notice sudden jumps to 150 bpm without an obvious trigger, that pattern is worth investigating. Conditions like SVT and atrial fibrillation are treatable, and an overactive thyroid is straightforward to diagnose with a blood test.