AI Summary

The phrase “exercise is medicine” is widely cited, yet the limits of beneficial activity are unclear. Researchers are asking whether extreme endurance events such as marathons or Ironman triathlons improve or harm cardiovascular health. To investigate, scientists have created the Micro‑Athlete mini‑heart, a heart‑on‑a‑chip that replicates human cardiac tissue. This device allows detailed study of how intense exercise may affect heart function and disease risk. The mini‑heart platform is expected to provide new insights into cardiovascular disease mechanisms.

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