Your target heart rate during exercise depends on your age and how intense you want your workout to be. For moderate-intensity exercise, aim for 50 to 70 percent of your maximum heart rate. For vigorous exercise, aim for 70 to 85 percent. These ranges come from the American Heart Association and give you a practical window to work within for most types of cardio.
How to Find Your Maximum Heart Rate
Everything starts with estimating your maximum heart rate, the theoretical ceiling your heart can hit during all-out effort. The simplest and most widely used formula is 220 minus your age. A 40-year-old, for example, would have an estimated max of 180 beats per minute (bpm).
That formula works well enough for most people, but it tends to underestimate max heart rate in older adults. A revised formula, 208 minus 0.7 times your age, was developed to correct for this. For a 40-year-old, the two formulas give similar results (180 vs. 180). But for a 60-year-old, the classic formula gives 160 while the revised one gives 166. If you’re over 50 and find the standard zones feel too easy, the revised formula may be a better starting point.
Target Heart Rate Zones by Intensity
Once you have your estimated max, multiply it by the percentage range that matches your goal.
- Moderate intensity (50 to 70% of max): This covers brisk walking, easy cycling, and casual swimming. You can hold a conversation but you’re clearly working. For a 40-year-old with a max of 180, that’s roughly 90 to 126 bpm.
- Vigorous intensity (70 to 85% of max): This is running, fast cycling, competitive sports, or any exercise that makes it hard to say more than a few words at a time. For that same 40-year-old, the range is about 126 to 153 bpm.
Here’s a quick reference for different ages, using the 220-minus-age formula:
- Age 25: Max 195. Moderate zone: 98–137. Vigorous zone: 137–166.
- Age 35: Max 185. Moderate zone: 93–130. Vigorous zone: 130–157.
- Age 45: Max 175. Moderate zone: 88–123. Vigorous zone: 123–149.
- Age 55: Max 165. Moderate zone: 83–116. Vigorous zone: 116–140.
- Age 65: Max 155. Moderate zone: 78–109. Vigorous zone: 109–132.
A More Personalized Calculation
The basic percentage method treats everyone with the same max heart rate identically, regardless of fitness level. The Karvonen method (also called heart rate reserve) adds a layer of personalization by factoring in your resting heart rate. It works like this: subtract your resting heart rate from your max heart rate to get your heart rate reserve, then multiply by your target percentage, then add your resting heart rate back.
Say you’re 40 years old with a resting heart rate of 60 bpm. Your heart rate reserve is 180 minus 60, which equals 120. To find 60 percent intensity: 120 times 0.60 equals 72, plus your resting rate of 60, gives you a target of 132 bpm. Compare that to the basic method, where 60 percent of 180 is just 108 bpm. The Karvonen method produces higher, more realistic targets because it accounts for the fact that a fitter person (with a lower resting heart rate) has more cardiovascular “room” to work with.
This approach is commonly used in cardiac rehabilitation programs, where patients typically aim for 60 to 80 percent of heart rate reserve. It’s also useful for anyone who finds the basic percentage zones don’t match how hard the workout actually feels.
When You Can’t Rely on Heart Rate Alone
Beta blockers and certain other blood pressure medications slow your heart rate, which means you may never reach your calculated target zone no matter how hard you push. If you take a beta blocker, your heart rate is artificially capped, and chasing a number can lead you to overexert yourself trying to hit a target that isn’t realistic for your situation.
The alternative is to use perceived exertion, essentially rating how hard the exercise feels on a scale of 6 to 20 (the Borg scale). A rating of 6 is no effort at all; 20 is absolute maximum. Moderate exercise typically falls around 12 to 14, the point where you’re breathing harder but can still talk. Vigorous exercise falls around 15 to 17, where conversation becomes difficult. Research shows a strong correlation between perceived exertion ratings and actual heart rate during progressive exercise, with the relationship holding well enough that multiplying your perceived exertion score by 10 gives a rough estimate of your heart rate. That correlation weakens during sustained, exhausting effort, but for everyday workouts, perceived exertion is a reliable backup.
Why Your Heart Rate Might Be Higher Than Expected
If your heart rate seems unusually high for a workout that normally feels manageable, external factors are often the cause. Heat is the biggest one. For every degree your core body temperature rises, your heart beats roughly 10 extra times per minute. That can mean a 10 to 17 percent increase in cardiac workload during extreme heat. Dehydration compounds the effect because your blood volume drops, forcing your heart to pump faster to deliver the same amount of oxygen.
Caffeine, poor sleep, stress, and illness can all push your resting and exercise heart rates higher than usual. If you notice your heart rate running 10 to 15 bpm above your normal range during a familiar workout, consider whether any of these factors are in play before assuming something is wrong. On hot or humid days, you can back off your pace to keep your heart rate in its usual zone, rather than pushing through at your normal speed and letting your heart rate climb unchecked.
Picking the Right Zone for Your Goal
For general cardiovascular health, staying in the moderate zone (50 to 70 percent of max) for at least 150 minutes per week is enough to get meaningful benefits. This is where most people should start, especially if you’re returning to exercise after a break or managing a chronic condition.
Vigorous exercise (70 to 85 percent of max) gives you more fitness gains per minute and is the standard for runners, cyclists, and anyone training for performance. The trade-off is that it’s harder to sustain, increases injury risk, and requires more recovery time. The health guidelines treat one minute of vigorous activity as roughly equivalent to two minutes of moderate activity, so 75 minutes of vigorous exercise per week provides similar benefits to 150 minutes at a moderate pace.
Staying above 85 percent of your max heart rate puts you in near-maximal territory. Short intervals at this intensity can build speed and power, but spending extended time here isn’t necessary for health and isn’t sustainable for most people. If you consistently find yourself above 85 percent during workouts that should feel moderate, your max heart rate estimate may be off, or something else (heat, medication, dehydration) is inflating the numbers.