A good heart rate while exercising falls between 50% and 85% of your maximum heart rate, depending on how hard you’re pushing. For most people, that translates to roughly 95 to 170 beats per minute (bpm), though your specific range narrows based on your age. Where you land within that window depends on your fitness goals and the type of workout you’re doing.
How to Find Your Maximum Heart Rate
Your target zone starts with one number: your estimated maximum heart rate. The simplest formula is 220 minus your age. A 40-year-old, for example, has an estimated max of 180 bpm. This formula, developed by Fox in the 1970s, remains the most widely used because it’s easy to remember, but it’s a rough estimate. It can be off by 10 to 12 beats in either direction for any individual.
Several alternative formulas exist that tend to be more accurate across different age groups. The Tanaka formula (208 minus 0.7 times your age) and the Gellish formula (207 minus 0.7 times your age) perform better for older adults, whose max heart rates the classic formula tends to underestimate. For women specifically, the Gulati formula (206 minus 0.88 times your age) was developed using female-only data. All of these are still estimates. If precision matters to you, a supervised exercise stress test gives the most reliable number.
Moderate vs. Vigorous Intensity Zones
Once you know your estimated max, the American Heart Association breaks exercise intensity into two main zones. Moderate intensity sits at 50% to 70% of your max. Vigorous intensity runs from 70% to 85%. Moderate intensity feels like a brisk walk or easy bike ride, where you can hold a conversation but you’re breathing harder than normal. Vigorous intensity is the territory of running, fast cycling, or competitive sports, where talking becomes difficult.
The AHA recommends at least 150 minutes per week of moderate-intensity activity or 75 minutes of vigorous activity, or some combination of both. Doubling that to 300 minutes per week provides additional benefits. Adding muscle-strengthening exercises on at least two days rounds out the picture.
Target Heart Rate by Age
Here’s what the full exercise range (50% to 85% of max) looks like at different ages, based on the AHA’s chart:
- Age 20: 100 to 170 bpm
- Age 30: 95 to 162 bpm
- Age 35: 93 to 157 bpm
- Age 40: 90 to 153 bpm
- Age 45: 88 to 149 bpm
- Age 50: 85 to 145 bpm
- Age 55: 83 to 140 bpm
- Age 60: 80 to 136 bpm
- Age 65: 78 to 132 bpm
- Age 70: 75 to 128 bpm
The lower end of each range represents the floor for moderate exercise. The upper end represents vigorous effort. If you’re just starting a fitness routine, aim for the lower half. As your cardiovascular fitness improves over weeks and months, you can push toward the higher end.
A More Personalized Calculation
The standard percentage-of-max approach treats everyone the same age as identical, which they obviously aren’t. A more personalized method factors in your resting heart rate, which reflects your current fitness level. This approach, called the Karvonen method, uses what’s known as heart rate reserve: the difference between your maximum heart rate and your resting heart rate.
To use it, subtract your resting heart rate from your estimated max. Multiply that number by the percentage of intensity you want (say, 60% for moderate effort), then add your resting heart rate back. For a 40-year-old with a resting rate of 65 bpm aiming for 60% intensity, that looks like: (180 minus 65) times 0.60, plus 65, which equals 134 bpm. Someone the same age with a resting rate of 80 bpm would get a different target of 140 bpm. This method is commonly used in cardiac rehabilitation programs, where patients typically aim for 60% to 80% of heart rate reserve.
To measure your resting heart rate accurately, check your pulse first thing in the morning before getting out of bed. Count beats for a full 60 seconds, or for 30 seconds and multiply by two. Do this on several mornings and average the results.
Why Medications Change the Rules
If you take beta-blockers for high blood pressure, heart conditions, or anxiety, the standard heart rate zones don’t apply to you. Beta-blockers lower both resting and exercise heart rate by roughly 18% to 19%. In one large study, people on beta-blockers had a resting heart rate about 14 bpm lower than those not taking the medication, and their maximum heart rate during exercise was 19% lower (averaging 116 bpm versus 145 bpm).
This doesn’t mean you’re getting a weaker workout. Your heart compensates by pumping more blood per beat, with oxygen delivery per heartbeat increasing by about 19.5%. But it does mean a standard target heart rate chart will overestimate where you should be. If you’re on beta-blockers or other heart-rate-lowering medications, the perceived exertion method (gauging effort by how hard the exercise feels rather than by a number) is often more useful than chasing a specific bpm.
How Accurate Is Your Watch?
Most people now track heart rate with a wrist-worn device, and accuracy varies more than you might expect. In a study comparing commercial monitors against a medical-grade ECG, chest straps came out on top, with the Polar H7 achieving 98% agreement with the ECG reading. Among wrist-worn devices, the Apple Watch performed best at 96% agreement, while other wrist devices like the Fitbit and Garmin models came in around 89%.
The important caveat: wrist-worn accuracy drops as exercise intensity increases. At rest, all devices performed well. But at higher treadmill speeds (8 to 9 mph), none of the wrist-worn devices maintained strong accuracy. Some devices also showed consistent bias. One Garmin model underestimated heart rate by about 2 bpm on average, while a TomTom model overestimated by 6 bpm. If you’re doing high-intensity interval training and want reliable numbers, a chest strap paired with your watch or phone will give you the most trustworthy data.
Signs You’re Pushing Too Hard
Exceeding your target zone briefly during a sprint or tough interval isn’t inherently dangerous for a healthy person. But certain symptoms signal that your body is struggling, regardless of what the number on your wrist says. Dizziness, lightheadedness, chest pain, heart palpitations (a pounding or fluttering sensation), nausea, or feeling faint are all reasons to stop immediately and rest. Shortness of breath that seems out of proportion to your effort level also warrants attention.
If you experience chest pain, difficulty breathing, a feeling that your heart is pounding uncontrollably, or you feel faint during exercise, seek medical attention promptly. These symptoms can indicate an abnormally fast heart rhythm that isn’t simply the expected response to physical activity.