How it works
Heart rate zones split your effort into five bands, from very easy to all-out. Working them out takes two steps.
First, your maximum heart rate. Your own measured maximum is best. Without one, a formula gives an estimate from age. This calculator offers the Tanaka formula, from a 2001 study that pooled data from many earlier studies, and the older 220 − age rule.
Second, the zones. There are two common ways to turn a maximum into zones:
- Percent of max takes 50, 60, 70, 80 and 90 percent of your maximum as the zone edges. Most sports watches use this by default.
- Heart rate reserve, also called the Karvonen method, first subtracts your resting heart rate. The reserve is the gap between resting and maximum, and the zones are percentages of that gap added back onto your resting rate. Because resting heart rate usually falls as aerobic fitness improves, this method follows your fitness more closely.
The formula
Tanaka: max HR = 208 − 0.7 × age
Traditional: max HR = 220 − age
Percent of max: target = max HR × percent
Reserve method: target = (max HR − resting HR) × percent + resting HR
Zone edges: 50%, 60%, 70%, 80%, 90%, 100%Worked example
A 35-year-old runner with a resting heart rate of 60.
- Tanaka estimate: 208 − 0.7 × 35 = 183.5, shown as 184 bpm.
- Percent of max, zone 2 (60 to 70%): 183.5 × 0.6 = 110 and 183.5 × 0.7 = 128, so 110 to 128 bpm.
- Reserve method, zone 2: (183.5 − 60) × 0.6 + 60 = 134 and (183.5 − 60) × 0.7 + 60 = 146, so 134 to 146 bpm.
The reserve method gives higher numbers for the same zone because it builds up from the resting rate rather than from zero.
Questions
Which max heart rate formula should I use?
If you know your real maximum, use it. Between the two formulas, Tanaka and colleagues found their version matched measured data better, especially in older adults. The two agree at age 40, where both give 180. Below 40, 220 − age gives a higher number, and above 40 a lower one.
How accurate are age-based formulas?
They describe averages. Your own maximum can sit well above or below the estimate, which is why zones from a formula are a starting point. If easy runs in zone 2 feel hard, or zone 4 feels easy, your real maximum probably differs from the formula.
How do I find my real max heart rate?
The most reliable way is a supervised exercise test. Many runners use the highest heart rate recorded in the final minutes of an all-out race. If you have a heart condition or are new to hard exercise, speak to a doctor before any maximal effort.
What is zone 2 training?
Easy aerobic running, usually at an effort where you can hold a conversation. It is the zone most endurance training plans use for easy and long runs. Zone numbers mean different things in different systems, so check which model a plan uses.
Why do my watch zones look different?
Watches may use percent of max, heart rate reserve or zones based on lactate threshold, and they may estimate your maximum differently. Set the same method and maximum on the watch and the numbers will match.
Do medications change heart rate zones?
Yes. Some medicines, such as beta blockers, lower heart rate, so zones from a formula will not fit. Ask your doctor how to judge effort if you take medication that affects heart rate.
Sources
- Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. Journal of the American College of Cardiology. 2001;37(1):153-156.
- Karvonen MJ, Kentala E, Mustala O. The effects of training on heart rate; a longitudinal study. Annales Medicinae Experimentalis et Biologiae Fenniae. 1957;35(3):307-315.