How many heartbeats does a mouse have? - briefly
A typical laboratory mouse beats about 500–600 times per minute, amounting to roughly 260 million heartbeats each year. Over an average two‑year lifespan this totals approximately 5 × 10⁸ beats.
How many heartbeats does a mouse have? - in detail
A laboratory mouse typically beats between 500 and 700 times per minute when at rest. The rate rises sharply during activity, reaching 800–900 beats per minute in young, healthy individuals.
Assuming an average resting rate of 600 beats per minute, a mouse that lives 2 years (≈ 1,050 days) will experience:
- Daily beats: 600 × 60 × 24 = 864,000
- Annual beats: 864,000 × 365 ≈ 315 million
- Total for 2 years: ≈ 630 million heart contractions
If the animal survives only 18 months, the cumulative total drops to roughly 475 million beats; a longer‑lived specimen (up to 3 years) may exceed 950 million.
Several variables modify these figures:
- Age: Neonates beat 800–1,200 times per minute; the rate declines to adult levels by 4 weeks.
- Ambient temperature: Lower temperatures induce tachycardia; a 5 °C drop can increase rate by 10–15 %.
- Strain: Inbred lines such as C57BL/6 show slightly slower rates (≈ 580 bpm) compared with outbred CD‑1 mice (≈ 640 bpm).
- Stress and handling: Acute stressors raise the heart rate by 20–30 % for several minutes.
Heart‑rate monitoring is performed with electrocardiography (ECG) electrodes or infrared plethysmography. Data are usually recorded in 5‑minute segments, averaged, and corrected for body temperature. Published studies consistently report resting rates within the 500–700 bpm window, confirming the calculations above.