He’s made of steel, but his heart’s another issue

“Superman Returns,” Warner Bros., July 2006

The premise:

AFTER returning to Earth from an extended sojourn, Superman (Brandon Routh) saves a space shuttle and its carrier jumbo jet from disaster, is assaulted by and prevails over criminals (in an incredibly vivid scene, his invulnerability to bullets is depicted as one is actually flattened by his eyeball), and is attacked by the evil Lex Luthor (Kevin Spacey). Luthor has discovered tiny remnants of Superman’s home planet of Krypton that glow an unearthly green and make Superman ultra-vulnerable, and uses them with crystals from Krypton to build an expanding island that threatens to supplant North America. In trying to rid Earth of this island, Superman comes close to death and is brought to Metropolis General Hospital for treatment.

The medical questions:

IS the vivid portrayal of the effects on the passengers of the airplane’s plummet accurate medically? Once wounded with kryptonite and suffering like any human, is Superman’s treatment in the hospital appropriate?

The reality:

IN the wake of lost cabin pressure, passengers subject to the cold and the sudden lack of oxygen at high altitude over several minutes as the plane falls would not be breathing comfortably as the film depicts. In reality, most if not all passengers would have difficulty breathing, would have lost consciousness and would have turned blue from frostbite. Many would likely not survive, even with Superman there to land the plane in Yankee Stadium.

As far as Superman’s own near-death experience, it is excellent medicine that the doctors who treat him search for wounds and discover and remove the last shred of kryptonite. It is less believable that doctors would administer a shock to the heart after it had already stopped beating entirely, because the purpose of the shock is to correct an aberrant rhythm, not to jolt a dead heart back to life. Only rarely is a “still” heart shocked, as a desperation move, and it’s not generally expected to succeed.

As Superman recovers, the monitor shows his heart rate as 40 beats per minute. This may seem slow, but it’s actually the rate of some athletes who exercise vigorously.

President Bush, who engages in brisk daily exercise, has a heart rate that has been clocked in the mid-40s (an average person’s heart rate is 70 beats per minute for men, 75 beats per minute for women).

After all, a well-developed exercising heart can deliver a greater volume of blood at a slower rate -- and no one exercises more vigorously than Superman.

Dr. Marc Siegel is an internist and an associate professor of medicine at New York University’s School of Medicine. He is also the author of “False Alarm: The Truth About the Epidemic of Fear.” In the Unreal World, he explains the medical facts behind the media fiction.