Heart rate zones are training intensity ranges defined as percentages of your maximum heart rate (MHR), typically divided into 5 zones from easy recovery to maximum effort.
The Five Zones
- Zone 1 (50-60% MHR): Recovery — very easy, conversational pace
- Zone 2 (60-70%): Aerobic base — fat burning, endurance building
- Zone 3 (70-80%): Tempo — moderate effort, improves efficiency
- Zone 4 (80-90%): Threshold — hard effort, builds speed and power
- Zone 5 (90-100%): Maximum — all-out sprints, very short duration
Calculating Your Max Heart Rate
The simplest estimate: MHR = 220 − age. For a 35-year-old: 220 − 35 = 185 bpm. More accurate formulas exist (Tanaka: 208 − 0.7 × age), and a lab test provides the most precise measurement.
Real-World Example
A 40-year-old runner with MHR of 180 bpm. Zone 2 (endurance): 108-126 bpm. Zone 4 (threshold): 144-162 bpm. Most training (80%) should be in Zones 1-2, with 20% in higher zones for speed development.
Frequently Asked Questions
Which heart rate zone burns the most fat?
Zone 2 (60-70% MHR) uses the highest percentage of fat for fuel. However, higher zones burn more total calories per minute. For overall fat loss, total calorie expenditure matters more than the "fat burning zone."
How long should I train in each zone?
The 80/20 rule is widely used: 80% of training time in Zones 1-2 (easy) and 20% in Zones 3-5 (hard). This polarized approach builds endurance while allowing adequate recovery.
Is the 220-minus-age formula accurate?
It provides a rough estimate with a standard deviation of ±10-12 bpm. Some people have naturally higher or lower max heart rates. For precise training, consider a lab-based VO2 max test or a field test.