How fast does a mouse’s heart beat? - briefly
A typical laboratory mouse beats at roughly 500–600 bpm at rest, rising to 700 bpm or more during activity. Strain, age, and physiological state can cause modest variations around this range.
How fast does a mouse’s heart beat? - in detail
The cardiac rhythm of a laboratory mouse typically falls between 300 and 800 beats per minute (bpm) at rest. Young adults of common strains such as C57BL/6, BALB/c, and CD‑1 average around 500–600 bpm, while neonatal mice can exceed 800 bpm. Age, genetic background, ambient temperature, and stress level produce measurable variations.
Physiological determinants
- Temperature: Each 1 °C rise in core temperature raises the rate by roughly 10 bpm; maintaining a stable 37 °C environment is essential for reproducible measurements.
- Activity: Spontaneous locomotion or handling can double the frequency within seconds, reaching 900–1000 bpm during vigorous movement.
- Anesthesia: Inhalational agents (isoflurane, sevoflurane) depress cardiac output, lowering the rhythm to 250–350 bpm depending on concentration.
- Sex and hormonal status: Females in estrus exhibit slightly higher rates (≈10 bpm) than males, attributed to estrogenic modulation of autonomic tone.
Measurement techniques
- Electrocardiography (ECG): Surface electrodes or telemetry implants provide continuous recordings; telemetry offers high fidelity in freely moving animals.
- Photoplethysmography: Infrared sensors detect peripheral pulse waveforms, useful for short‑term assessments without surgical implantation.
- Ultrasound Doppler: High‑frequency transducers visualize blood flow in the aorta, allowing indirect calculation of heart rate from velocity waveforms.
Comparative perspective
A mouse’s heart beats roughly 10–15 times faster than an adult human’s average of 60–100 bpm. This acceleration supports the high metabolic demand of a small endotherm, delivering oxygen rapidly to tissues with limited diffusion distances.
Implications for research
Accurate knowledge of baseline cardiac frequency is crucial when interpreting cardiovascular drug effects, genetic modifications, or disease models such as hypertension or heart failure. Researchers must control temperature, handling, and anesthesia depth to avoid confounding fluctuations in the measured rhythm.