Zones, short for heart rate zones, measure how hard your body is working.
Heart Rate Zones
The most important thing to know about Heart Rate Zones is that, everyone's zones are unique to their max heart rate. A person in their 30s might have different zones than a person in their 40.
Each zone represents a range in numbers. These zones are based off of a percentage of your max heart rate.
Heart Rate Zones are represented by different zones or "levels" of your heart rate. It's an easy way to split up and understand how your heart rate is affecting your body. Here's the simplest explanation of each zone, with all data associated to it:
Zone 1
Keywords: Active Recovery | Very Easy | Fat Burning Zone
Heart Rate: 50-60% of your max heart rate.
Key Characteristics
This is the zone with the lowest heart rate and intensity. Usually the zone in question when someone mentions recovery, or warm-up. To train inside this zone, go for a walk or light cycling.
Zone 2
Keywords: Aerobic Endurance | Z2 | Base | Easy | Conversational Pace | Fat Burning Zone
Heart Rate: 60-70% of your max heart rate.
Key Characteristics
The benefit of zone 2 is that you can do a lot of it without a lot of fatigue. So you can do a lot of it, every day. Doing activity in this zone should be perceived as "comfortable".
Conversation in this zone should be relatively easy. Your breaths will be slightly heavier and more frequent than in zone one. If you're new to endurance sport, do at least 100K in this zone, before starting to incorporate more intense training. This is the zone you will want to spend the most of your time training in, as it helps your build your base endurance and creates a robust foundation.
Zone 2 is unique in its ability to assist you in burning a lot of fat, instead of carbohydrates. Meaning, you are fueled by fat in this zone, not carbs. The PERCENTAGE of fat burning is maxed out in zone 2 (at about 50-60%) but you actually burn more fat calories at a higher power. The trick to burning fat with zone 2 is that you can do a ton of hours of it without getting burnt out.
You get ravenously hungry because your body wants to replenish its glycogen stores, and a higher proportion of calories from glycogen are burned at higher heart rate zones.
Zone 3
Keywords: Tempo | Sweetspot | Moderate | Aerobic Power
Heart Rate: 70-80% of your max heart rate.
Key Characteristics
Think of the zone as your "sweetspot". By spending time in this zone, you ask your body to sustain stress, but no more, than it's able to handle for a long duration. Your mind will ask you questions about fatigue, and ask you run slower, while your body is perfectly capable of continuing.
You'll experience your breath become sharper and more concentration is required to maintain this effort. It gets harder to talk, annoyance is more pronounced, and you'll start to feel uncomfortable.
Zone 4
Keywords: Lactate Threshold | Threshold | Hard
Heart Rate: 80-90% of your max heart rate.
Key Characteristics
Conversation while doing activity in this zone should/will be difficult. Breathing will be heavy, but you'll not gasp for air. Concentration is required to stay in this zone, so it's usually broken down into blocks or intervals of 10 to 30 minutes.
It's recommended to plan an easy day or recovery activity of 30-60 minutes the day after a Z4 session.
Zone 5
Keywords: Anaerobic | Endurance | VO2 Max
Heart Rate: 90-100% of your max heart rate.
Key Characteristics
Conversation should not take place in this zone at all. It's painful to do activity in this zone for more than a few minutes. Breathing should be heavy, and the effort required to maintain this will be near impossible for a long duration.
The reason why is because in this zone you will have reached the maximum volume of oxygen your body can consume, or, the point of your body's VO2 max.
Zone 6
Keywords: Anaerobic Capacity | Sprint
Heart Rate: < 121% of your max heart rate.
Key Characteristics
Your form will shift from controlled, to sprint. Activity in this zone is hard to reach, some will never experience this level of effort. Activity in this zone requires a different way of thinking, and a different way of moving.