The heart is a muscle capable of both the quick contraction of white muscle cells, and also the endurance of red muscle cells. Why haven't more muscles in the body adapted the same combo of abilities? Is there a known weakness to the heart muscle? Excessive energy consumption, or something else?

  • $\begingroup$ Different strokes for different folks, as they used to say. $\endgroup$ – David Sep 2 at 15:01
  • $\begingroup$ Our heart, diaphragm, and arterial muscles need to work 24/7. No other muscles even come close to that requirement, so they evolved in different ways. Always be wary of asking Why? when it comes to evolution. $\endgroup$ – MattDMo Sep 2 at 19:54