# Towards Accurate Reference Values for Heart Rate and Speed Zones by Aerobic Fitness and Sex in Long-Distance Runners

## TL;DR

This study provides reference values for heart rate and running speed zones in long-distance runners, showing differences based on sex and performance level.

## Contribution

The study offers evidence-based reference ranges for training intensities in endurance runners, considering sex and performance level differences.

## Key findings

- Heart rate at VT2 occurs at 93.5% of peak heart rate, and at VT1 at 85.1%.
- Men's beginners have higher relative HR and VO2 values at thresholds compared to elites, while women show more stability.
- Running speed at VT2 is 87.6% of VO2peak speed, and at VT1 is 73.9%.

## Abstract

Background: This study aimed to provide reference values for estimating training intensities in long-distance runners based on progressive incremental tests, considering differences related to sex and performance level. Methods: A total of 1411 endurance-trained runners (819 men and 592 women) completed a standardized treadmill protocol with gas exchange analysis to determine ventilatory thresholds and peak oxygen consumption (VO2peak). Heart rate (HR) and running speed at each threshold were expressed relative to their peak values. Results: HR at second ventilatory threshold (VT2) occurred at 93.5 ± 2.5% of HR peak, and HR at first ventilatory threshold at 85.1 ± 4.6%. The relative running speeds at VT2 and VT1 corresponded to 87.6 ± 3.9% and 73.9 ± 5.5% of the speed at VO2peak, respectively. In men, beginners exhibited higher relative HR and VO2 values at the ventilatory thresholds than elite runners. In contrast, women displayed higher and more stable relative values across performance levels. Conclusions: These findings establish precise, evidence-based reference ranges derived from a large cohort of runners and highlight the need to consider sex and performance level when estimating exercise intensities. Individualized physiological assessment remains essential for accurate training prescription and performance optimization.