Heart Rate Zones: The 5 Training Zones Explained

Heart rate zones turn a vague instruction like "run easy" or "go hard" into a specific bpm range you can hold and verify on a watch. There are five of them, and every zone is defined the same way: as a slice of your maximum heart rate. Get your max HR right and the five zones fall out automatically.

What are heart rate zones?

Heart rate zones are five intensity bands, each defined as a percentage of your maximum heart rate. Zone 1 is 50 to 60 percent (recovery), Zone 2 is 60 to 70 percent (aerobic base), Zone 3 is 70 to 80 percent (tempo), Zone 4 is 80 to 90 percent (threshold), and Zone 5 is 90 to 100 percent (VO2 max). Each zone trains a different physiological system.

The zones are not arbitrary. Each boundary lines up with a metabolic shift, the point where your body changes how it produces and clears energy. Training inside a specific zone tells your body which adaptation to build.

Zone	% of max HR	Name	What it trains
1	50 to 60%	Recovery	Active recovery, blood flow
2	60 to 70%	Aerobic base	Fat metabolism, mitochondrial density
3	70 to 80%	Tempo	Aerobic capacity, stamina
4	80 to 90%	Threshold	Lactate clearance, race pace
5	90 to 100%	VO2 max	Maximum aerobic power, speed

The five heart rate zones explained

Each zone has a distinct purpose. Zones 1 and 2 build the aerobic engine and should make up the bulk of training. Zone 3 is the "gray zone" most athletes overuse. Zone 4 sharpens race pace and lactate tolerance. Zone 5 is brief, brutal, and reserved for short intervals that raise your aerobic ceiling.

• Zone 1 (50 to 60%): Walking, warm-ups, cool-downs, recovery spins. You can hold a full conversation comfortably. Its job is circulation and recovery, not fitness gains.
• Zone 2 (60 to 70%): The aerobic base zone. Conversational but with mild effort. This is where mitochondrial density and fat-burning efficiency improve. Most endurance volume lives here.
• Zone 3 (70 to 80%): Tempo. Comfortably hard. You can speak in short phrases. Useful in moderation, but it is the zone athletes drift into by accident, getting fatigued without the focused benefit of Zone 2 or Zone 4.
• Zone 4 (80 to 90%): Threshold. The pace you could hold for roughly an hour all-out. Speaking is reduced to a few words. This zone raises the intensity you can sustain before lactate accumulates faster than you clear it.
• Zone 5 (90 to 100%): VO2 max and anaerobic. All-out intervals of 30 seconds to 5 minutes. No talking. Builds top-end aerobic power and speed.

Heart rate zones by age

Because zones are a percentage of max heart rate, and max HR declines roughly 1 beat per year, every zone shifts down with age. Using the common 220-minus-age estimate, a 30-year-old has a Zone 2 of 114 to 133 bpm, while a 50-year-old has a Zone 2 of 102 to 119 bpm. The table below gives all five zones by age.

Age	Max HR	Z1 (50-60%)	Z2 (60-70%)	Z3 (70-80%)	Z4 (80-90%)	Z5 (90-100%)
20	200	100-120	120-140	140-160	160-180	180-200
25	195	98-117	117-137	137-156	156-176	176-195
30	190	95-114	114-133	133-152	152-171	171-190
35	185	93-111	111-130	130-148	148-167	167-185
40	180	90-108	108-126	126-144	144-162	162-180
45	175	88-105	105-123	123-140	140-158	158-175
50	170	85-102	102-119	119-136	136-153	153-170
55	165	83-99	99-116	116-132	132-149	149-165
60	160	80-96	96-112	112-128	128-144	144-160
65	155	78-93	93-109	109-124	124-140	140-155

Max HR estimated with 220 minus age. For a deeper age breakdown of the most-used zone, see Zone 2 heart rate by age.

How to calculate your heart rate zones

Calculating your zones takes two numbers: your maximum heart rate and (for the more accurate Karvonen method) your resting heart rate. The simple method multiplies max HR by each zone percentage. The Karvonen method uses heart rate reserve and produces personalized ranges that are typically 5 to 12 bpm higher, especially for athletes with low resting heart rates.

Simple method (percentage of max HR)

Take your max HR and multiply by each boundary. For a max HR of 190: Zone 2 is 190 x 0.60 to 190 x 0.70, or 114 to 133 bpm. Fast, but it ignores your resting heart rate.

Karvonen method (heart rate reserve)

This accounts for fitness by using your heart rate reserve (max HR minus resting HR):

Zone bpm = (max HR minus resting HR) x zone% + resting HR

For a max HR of 190 and resting HR of 50, heart rate reserve is 140. Zone 2 becomes (140 x 0.60) + 50 to (140 x 0.70) + 50, or 134 to 148 bpm, noticeably higher than the 114 to 133 from the simple method.

The heart rate zone calculator runs both methods side by side so you can compare. To get an accurate max HR instead of the age formula, see the field-test protocol in what heart rate is Zone 2.

Why the age formula can be off by 7 bpm

The 220-minus-age formula has a standard deviation of roughly 10 to 12 bpm across the population. That means your true max HR could sit a full zone-width away from the estimate, pushing each zone boundary off by 7 to 8 bpm. For a number you train to every day, a measured max HR is worth the one hard test it takes to get it.

3-zone vs 5-zone model: which should you use?

The 5-zone model is best for structured workouts and racing, where you want to target threshold or VO2 max precisely. The 3-zone model (easy, moderate, hard) is better for managing overall training distribution and avoiding the gray zone. Many coaches program with 3 zones and verify intensity with 5.

The 3-zone model maps cleanly onto the 5-zone version: easy covers Zones 1 to 2, moderate is Zone 3, and hard is Zones 4 to 5. The advantage of the simpler model is that it makes the single most important training rule obvious: most of your time belongs in "easy," and very little in "moderate."

How much time to spend in each zone

The most consistent finding in endurance research is the 80/20 rule: roughly 80 percent of training time in Zones 1 to 2 and 20 percent in Zones 4 to 5, with Zone 3 kept deliberately small. For someone training 6 hours a week, that is about 4 hours 48 minutes easy and 72 minutes hard, with tempo work used sparingly.

Weekly hours	Zones 1-2 (80%)	Zones 4-5 (20%)
4	3 h 12 m	48 m
6	4 h 48 m	1 h 12 m
8	6 h 24 m	1 h 36 m
10	8 h	2 h

The mistake that wrecks most amateur training is spending 40 to 50 percent of the week in Zone 3: too hard to recover from, too easy to drive top-end gains. Polarizing toward the ends of the range, hard hard and easy easy, produces more fitness from the same hours.

Heart rate zones for running vs cycling

Your cycling max heart rate is typically 5 to 10 bpm lower than your running max, because cycling is non-weight-bearing and uses less muscle mass. Calculate and store separate zones for each sport. A single bpm number that is correct for running will read as one zone too high when applied to the bike.

This matters most for triathletes and anyone who cross-trains. If you set your bike zones from a running max HR, your "Zone 2" rides will actually sit in Zone 1, and your hard efforts will fall short of true threshold. Run a max effort in each sport, or at minimum subtract about 8 bpm from your running max to estimate cycling zones, then refine from there. For the cycling power equivalent, see FTP zones and the 20-minute test.

Heart rate zones tell you how hard you are working today; your VO2 max sets the ceiling those zones are squeezed beneath. Train the zones consistently and the ceiling rises.

Frequently asked questions

What are the 5 heart rate zones?

The five heart rate zones are Zone 1 (50 to 60 percent of max HR, recovery), Zone 2 (60 to 70 percent, aerobic base), Zone 3 (70 to 80 percent, tempo), Zone 4 (80 to 90 percent, threshold), and Zone 5 (90 to 100 percent, VO2 max). Each band targets a different physiological adaptation.

How do I calculate my heart rate zones?

First find your maximum heart rate, either from the 220-minus-age estimate or a measured all-out field test. Then multiply that number by each zone percentage. For a more personalized result, use the Karvonen method, which factors in your resting heart rate and heart rate reserve.

What is the best heart rate zone for fat burning?

Zone 2, at 60 to 70 percent of max heart rate, burns the highest proportion of calories from fat and is the most sustainable training intensity. Higher zones burn more total calories but a smaller fraction from fat, and cannot be maintained long enough to build aerobic efficiency.

How accurate is the 220-minus-age formula?

It is a rough estimate with a standard deviation of about 10 to 12 bpm, so your true max heart rate could be a full zone-width away from the prediction. For training you do every day, a measured max HR from a hard field test is far more reliable than the formula.

Are running and cycling heart rate zones the same?

No. Cycling max heart rate is usually 5 to 10 bpm lower than running max because it is non-weight-bearing and recruits less muscle mass. Set and store separate zones for each sport, or your bike efforts will consistently read one zone too high.