George Foreman’s remarkable comeback after a 10-year hiatus from boxing is one of the sport’s greatest success stories. It also might have been the worst thing to happen to other relatively old fighters.

Aging fighters often use Foreman’s victory over Michael Moorer at 45 years old to regain the heavyweight championship two decades after he lost it to Muhammad Ali as an example of what they believe they too can accomplish at middle age.

The problem is that they rarely consider the increased risk they take every time they step through the ropes, as one look at Ali today illustrates.

Fighters such as Evander Holyfield and Riddick Bowe, who continue to fight into their 40s, have a right to pursue their boxing licenses but it is the job of the boxing commissions to determine with diligence whether they would be in undue danger in the ring.

Even in Foreman’s case, there was concern on the part of the sanctioning bodies and Nevada State Athletic Commission when he sought his license to fight Moorer, almost 20 years his junior.

Foreman underwent extensive testing, including multiple brain scans. At the time, I was the neurological consultant for the commission. His exams resembled those of a 20 year old. Perhaps it was genetic or his hiatus from the ring that spared him the wear and tear experienced by gym rats who spar regularly.

Clearly, Foreman was an anomaly. Yet countless other older fighters followed his lead, which continues to pose a significant challenge to those charged with protecting these athletes.

In evaluating an aging fighter’s career, we often forget the damage incurred in the amateurs. Most boxers begin their careers in their early teens or younger and despite head gear and shorter rounds and fights, studies show amateur fighters face substantial danger.

A Swedish study that appeared in the September 2007 issue of the Archives of Neurology focused on 14 amateur boxers. The results revealed damage to neurons and other cells important to brain function within 7-10 days and as long as 3 months after a bout (despite rest from sparring). However, clinically, the fighters had normal examinations.

One can only imagine what these results would be like in professional fighters who might spar 100 rounds or more before a bout.

In a boxer, regardless of ability, the inevitable aging process is superficially evident by an increased susceptibility to cuts and facial swelling. Reflexes are slowed, so it becomes more difficult to avoid a punch. And it becomes more difficult to recover after taking a solid punch or punches.

Boxing experts pay close attention to a fighter’s legs; many believe they’re the first thing to go as a fighter ages. This might apply less to heavyweights, who remain more stable during a bout than lighter-weight boxers who rely on activity to get the job done.

There also is a certain amount of brain shrinkage with advancing age. In a boxer over 40, even normal brain cell loss can increase their susceptibility to brain hemorrhage.

Tiny veins, called “bridging veins,” connect the brain to a leathery covering that surrounds it (dura). As the brain shifts from trauma, these veins are pulled or stretched. In an older, shrunken brain, the veins are more taut. With subsequent force, they are more likely to pull away and bleed along the brain’s surface – the major cause of death in a boxer.

Furthermore, the punishment absorbed by a boxer’s brain today might not become evident until years after retirement from the ring. This might be why former heavyweight champion Floyd Patterson, for example, was able to function as Chairman of the New York State Athletic Commission for some time until his cognitive function rapidly deteriorated over a few years.

So what is to be done?

A license to box must be earned, like a driver’s license. A fighter must demonstrate skill. If he has it, he can fight. If his skill has diminished substantially, he can’t fight. Simple as that.

New York tried to suspend Holyfield in 2004 following a dreadful loss to Larry Donald that revealed substantially diminished skills. The state rescinded the medical suspension when Holyfield passed medical evaluations, something he had done countless times before. Not only was the bar set too low; it was the wrong bar.

Medical tests performed on boxers can’t replicate the stress on the body endured during a vigorous 12 rounds. And by the time exams indicate abnormality, such as cognitive testing that evaluates detailed brain functioning, it is often too late.

Still, athletic commissions try to hang their hat on these results to justify approving a bout. They want their decisions to hold up in a legal challenge. Chronological age cannot be used, but “ring age,” the wear and tear on an athlete who has had too many tough matches, will count.

As a result of weakness, laziness, fear of reprisal from a promoter or loss of tax revenue, commissions frequently cave in or have their medical boards make such decisions. In the end, they often allow susceptible fighters to face weak opponents; they approve fewer rounds; or two aged boxers are licensed to compete against one another.

One hopes the boxer, or people around him, will help the athlete make the right decision. However, often it is difficult to recognize reality. For the fighter, pride typically interferes. And for the handlers who rely on fighters for their pay checks, an uncertain future can cloud their judgment.

The issue isn’t whether Holyfield (46) can beat a fighter like Nicolay Valuev or Bowe (41) can win an eight-round decision against an unknown. That doesn’t prove either way whether they should hold licenses. The important criterion is how far their skill levels have deteriorated from what they once were.

That’s a determination boxing commissions must make. It might not be fun or win many accolades, but it is absolutely necessary – regardless of how many tickets the fighters can still sell.

Dr. Margaret Goodman is a practcing neurologist in Las Vegas. She is a former Medical Advisory Board Chairman and Chief Ringside Physician for the Nevada State Athletic Commission