Establishing VO2peak-based exercise intensity classification and physiological validation in ICR mice

Area of Science:

• Exercise Physiology
• Animal Models
• Metabolic Research

Background:

• Accurate exercise intensity classification is crucial for rodent research.
• Standardized protocols are needed to ensure reproducibility in mouse studies.
• VO2peak (maximal oxygen consumption) is a key metric for exercise physiology.

Purpose of the Study:

• To develop a VO2peak-based framework for classifying exercise intensity in ICR mice.
• To validate physiological responses associated with different exercise intensities.
• To establish reliable speed thresholds for exercise interventions in mice.

Main Methods:

• Four maximal graded exercise test (GXT) protocols were performed on male ICR mice.
• VO2peak was measured using a treadmill-equipped metabolic chamber.
• Constant-load tests (CXT) were used to assess metabolic responses and blood lactate at varying intensities (40%, 60%, 80% VO2reserve).

Main Results:

• VO2peak values were comparable across most GXT protocols, with fixed-incline protocols showing less variability.
• Oxygen consumption and energy expenditure increased with exercise intensity during CXT.
• Blood lactate levels rose with intensity, exceeding the aerobic-anaerobic threshold at 60% VO2reserve.

Conclusions:

• Standardized VO2peak reference values were established for classifying exercise intensity in ICR mice.
• Fixed-incline GXT protocols are recommended for reduced variability in mouse exercise testing.
• The derived speed thresholds provide a foundation for future exercise interventions and research in mice.