Zone 2 pace for a 1:45 Half Marathon.
A worked estimate for runners using a 1:45 Half Marathon race benchmark. Your age, resting heart rate, terrain, and current fatigue can move the right target, so use this page as a starting point.
How to use this target
Zone 2 running should feel controlled and repeatable. Start at or slower than 6:22 /km, then use breathing and heart rate as checks rather than forcing the number on a hot, hilly, or fatigued day.
This estimate assumes age 35 and resting heart rate 50 because those values are not included in the race-time benchmark. Enter your own values in the full calculator for a more personal heart-rate range.
Build the aerobic base
Pair easy Zone 2 volume with occasional high-aerobic work such as the Norwegian 4×4 protocol. The goal is a sustainable training rhythm, not a pace you must defend every day.
Health and medical disclaimer
Health and Medical Disclaimer
The information, calculations, and training protocols provided by this website, including but not limited to pace estimates, heart-rate zones, and interval structures, are for educational and informational purposes only. They do not constitute medical advice, diagnosis, or treatment.
Always consult with a qualified healthcare professional or physician before beginning any new exercise program, especially high-intensity interval training (HIIT). If you experience faintness, dizziness, pain, or shortness of breath at any time while exercising, stop immediately and seek medical assistance.
Accuracy and assumption of risk
The physiological models used on this site, such as maximum-heart-rate formulas and aerobic-capacity estimates, are generalized mathematical models. They do not account for individual health conditions, environmental factors, or biomechanical differences. You acknowledge that running and high-intensity training carry inherent risks, including injury or death.
By using this tool, you assume 100% of the risk associated with using these calculations in your training.
Limitation of liability
Under no circumstances shall the creators, developers, or hosting providers of this website be held liable for any direct, indirect, incidental, or consequential damages, injuries, or health complications arising from your use of, or inability to use, the information and tools provided on this site. Use this tool entirely at your own risk.