Heart rate zones are intensity ranges based on your maximum heart rate (Max HR). Each zone activates different energy systems and physiological responses, helping athletes target endurance, strength, or speed more precisely. Do you know which zone you train in?

 

Estimating Max Heart Rate Most devices use “220 minus your age,” but this is a rough estimate. Factors like medication, hydration, stress, and sleep affect accuracy. Teen athletes especially can have variable heart rate responses. A better approach is tracking your peak heart rate during intense sessions over time.

 

Zone 1 – Recovery (50–60% of Max HR)

Very low intensity that boosts circulation and supports muscle repair without causing fatigue.

• Primary adaptation: Enhances blood flow to speed recovery.
• Effort profile: Easy and restorative movement.
• Breathing: Calm and steady; full sentences are easy.
• Examples: Warm-ups, cooldowns, light mobility work.

 

Zone 2 – Aerobic Base (60–70% of Max HR)

A steady state effort that improves cardiovascular efficiency and trains your body to burn fat as fuel.

• Primary adaptation: Builds endurance and mitochondrial capacity.
• Effort profile: Comfortable pace for longer durations.
• Breathing: Controlled and deeper than rest.
• Examples: Easy running, cycling, or swimming at a conversational pace.

 

Zone 3 – Moderate Effort (70–80% of Max HR)

Close to your aerobic limit, this zone develops stamina and muscular endurance.

• Primary adaptation: Enhances oxygen use and early lactate processing.
• Effort profile: Challenging but manageable.
• Breathing: Noticeably heavier; short phrases only.
• Examples: Tempo runs, steady bike efforts, swim intervals.

 

Zone 4 – Threshold (80–90% of Max HR) *

Training near your lactate threshold, where lactate builds faster than it clears.

• Primary adaptation: Increases VO₂ max and lactate tolerance.
• Effort profile: Hard and focused; sustainable for minutes.
• Breathing: Labored; speech limited to single words.
• Examples: Cruise intervals, hill repeats, time trials.

 

Zone 5 – Max Effort (>90% of Max HR) *

All-out efforts that develop speed and anaerobic power.

• Primary adaptation: Boosts anaerobic capacity and neuromuscular coordination.
• Effort profile: Explosive bursts lasting seconds, followed by full recovery.
• Breathing: Rapid and intense.
• Examples: Max sprints, explosive drills, sport-specific bursts.

 

**Because teens are still growing, high-intensity training (especially zones 4 and 5) should be done sparingly and under coach supervision.

 

 

 

References

1. Cleveland Clinic. Exercise Heart Rate Zones Explained. Health Essentials from Cleveland Clinic. Published December 12, 2023. https://health.clevelandclinic.org/exercise-heart-rate-zones-explained
2. Mahaffey K. Heart Rate Zones: Do They Work or Not? blog.nasm.org. https://blog.nasm.org/heart-rate-zones-do-they-work-or-not
3. Marx AJ, Porcari JP, Doberstein S, Bramwell S, Foster C, Green DJ. The Accuracy of Heart Rate–Based Zone Training Using Predicted versus Measured Maximal Heart Rate. Acefitness.org. Published 2020. Accessed October 18, 2025. https://www.acefitness.org/continuing-education/certified/research/7466/the-accuracy-of-heart-rate-based-zone-training-using-predicted-versus-measured-maximal-heart-rate/?srsltid=AfmBOopnDOiLblRCRQFydw8Zq-1YCh7ReKGIZO2RokJJk8ePV9ffS5bP