Target Heart Rate for Exercise Explained (and the Fat-Burning Zone Myth)
Heart rate zones turn exercise intensity into numbers you can actually train by. Knowing your target heart rate helps you work hard enough to improve without overdoing it — and it lets us clear up one of fitness's most persistent myths along the way.
Finding your zones
Zones are based on your maximum heart rate, often roughly estimated as 220 minus your age — a useful approximation, not a precise figure. Your target zones are then percentages of that maximum: moderate intensity is commonly about 50 to 70%, and vigorous intensity about 70 to 85%. A 40-year-old with an estimated max of 180 would target roughly 90 to 153 beats per minute across those zones.
What each zone is good for
- Moderate (about 50 to 70%): comfortable, conversational effort, great for building an aerobic base and sustainable for long sessions.
- Vigorous (about 70 to 85%): harder breathing, improves fitness faster, best in shorter bouts or intervals.
- Very high (above 85%): for short, intense efforts and intervals, used sparingly.
The fat-burning zone myth
Lower-intensity exercise does burn a higher proportion of its calories from fat, which is where the fat-burning zone idea comes from. But higher-intensity exercise burns more total calories in the same time, so it often burns more fat overall. For weight loss, what matters most is total calories burned and your overall diet — not staying in a magic zone. Train at the intensity you enjoy and can sustain.
Is the 220-minus-age formula accurate?
It is a rough average and can be off by 10 to 20 beats per minute for an individual. Use it as a starting guide; if you train seriously, perceived effort and how you feel are valuable companions to the numbers.
Which zone should I train in?
A mix works best for most people: plenty of comfortable moderate work for your base, with some harder sessions to push fitness. The best zone is ultimately the one that keeps you exercising consistently.
The bottom line
Target heart rate zones, built from your estimated maximum, help you train at the right intensity — moderate for your base, vigorous to push fitness. Ignore the fat-burning-zone myth: total calories and diet drive fat loss, not a single heart-rate band. Use our free calculator to find your zones and train by feel as well as numbers.