Cardio & Endurance Science Hub
Pace Calculations, Target Heart Rate Zones, VO2 Max, and Energy Expenditure
Cardiovascular calculators and endurance models for running pace splits, swimming performance projections, target heart rate zones, and caloric expenditure.
Cardio Calculators Calculators & Tools
Running Pace Calculator
Convert pace, distance, and time for any run or race.
Target Heart Rate Calculator
Find your exercise heart-rate zones from age and resting pulse.
Heart Rate Recovery & VO2 Calculator
Estimate recovery score and VO2 max from heart rate response.
Walking Calorie Calculator
Burn rate for walking based on distance, speed, and weight.
Swimming Calorie Calculator
Energy burn for every stroke style and intensity level.
Swimming Pace Calculator
Calculate splits and pace per 100m for pool and open water.
Swim Progress Predictor
Estimate future swimming speed and times based on frequency.
Understanding Cardio Calculators Science
Cardiovascular fitness is the cornerstone of aerobic capacity, metabolic efficiency, and long-term longevity. Evaluating cardio performance involves converting pace splits, computing energetic expenditure based on MET (Metabolic Equivalent of Task) values, and targeting optimal heart rate training zones.
Our cardio calculators utilize Pete Riegel's endurance prediction formula, Karvonen heart rate reserve equations, and clinical MET tables from the Compendium of Physical Activities to deliver precise endurance metrics.
Core Scientific Principles
Clinical & Academic Guidelines
AHA & ACSM Exercise Guidelines: The American Heart Association (AHA) recommends at least 150 minutes of moderate-intensity aerobic activity or 75 minutes of vigorous activity weekly to maintain cardiovascular health and lower cardiometabolic disease risk.
How to Apply These Tools
Convert your running splits with the Running Pace Calculator, establish your aerobic training bounds with the Target Heart Rate Calculator, and estimate pool caloric burn using the Swimming Calorie Calculator.
Scientific & Peer-Reviewed References
- Riegel PS. Athletic records and age. Am Sci. 1981;69(3):285-290.
- Ainsworth BE, et al. 2011 Compendium of Physical Activities: a second update of codes and MET values. Med Sci Sports Exerc. 2011;43(8):1575-1581.
- Piercy KL, et al. The Physical Activity Guidelines for Americans. JAMA. 2018;320(19):2020-2028.
Frequently Asked Questions
What is the difference between Zone 2 and Zone 5 cardio? +
Zone 2 (60-70% HRmax) builds mitochondrial density, fat oxidation, and aerobic base without excessive fatigue. Zone 5 (90-100% HRmax) taxes anaerobic metabolism, VO2 max capacity, and lactate clearance.
How does Riegel's formula predict marathon finish times? +
Riegel's formula applies a 1.06 exponent to account for continuous fatigue accumulation. It assumes you have completed appropriate volume training for the target distance.
Why is swimming lower impact than running? +
Water buoyancy supports ~90% of body mass, eliminating the ground reaction force impacts (2-3x body weight) experienced during running foot strikes.
Explore Other Categories
Fitness Calculators
Track strength, body composition, and physical benchmarks.
View category →Nutrition Calculators
Dial in calories, protein, and macros for your goal.
View category →Recovery Calculators
Train hard, recover smart, avoid burnout and injury.
View category →Body Recomposition
Plan muscle growth, fat loss targets, and body transformations.
View category →