"I think that's the thing people don't understand -- the heightened intensity does damage to your body, immune system, energy levels, on the fitness of your muscles, ligaments, tendons," Gimelstob said.
"It's just a very tough sport. I truly believe that Nadal, Murray, (Novak) Djokovic and Federer, these guys aren't only the best tennis athletes in the world, they are some of the best athletes in the world.
"There's a whole culture of being tough and strong and pushing through pain and being a warrior.
"But I can tell you right now at 37 years old walking my dog, my body feels the brunt of probably doing a lot of things and pushing through barriers I probably shouldn't have. That's the product of an individual sport."
At first Leslie Findley, a consultant neurologist in England who has treated marathon runners, footballers and tennis players with mono, said it was a "myth" that those involved in tennis are more vulnerable than other athletes.
But he subsequently acknowledged that when factoring in their travel, the severity of the illness can intensify.
"We know people with fatigue illnesses related to the effects of viruses travel badly," he said.
"If you take someone with a chronic fatigue syndrome and stick them on an airplane at (London's) Heathrow to the United States they'll do an eight-hour flight. That can have a devastating effect on them for days afterwards."
Preventing mono can be difficult, but Findley said it's important that players heed warnings. If they suddenly develop a cold, fever, sore throat or stomach issues, it's vital to rest instead of continuing to train and play matches.
Stopping not easy
As Gimelstob pointed out and Findley knows through his own experience in working with sportsmen and women, that isn't always easy.
"When you and I have the flu, we go to bed and within a week or two we'd be back to normal," Findley said.
"Why these people get symptoms that go on for weeks, months and years is usually because -- and I'm now generalizing -- they don't stop when they have the first symptoms and tend to push through, and they're under stress."
Diagnosing mono isn't simple, either, said Findley.
He said there is a lack of specialists and that doing a battery of tests at the outset may not be efficient. He will usually spend nearly two hours talking to patients in a first consultation before making a clinical diagnosis.
"Then there are a limited number of blood tests that need to be done to make sure there is nothing else contributing to it," Findley said.
The women's tennis tour said in an email that player health and well being was a "priority." But the age of many of its pros is another reason why tennis players would appear to be at risk.
"Mononucleosis most commonly occurs in people between the ages of 15 and 24, which is our athlete population," said Kathleen Stroia, senior vice president, sport sciences and medicine & transitions, with the WTA.
The men's tour said in an email that mono "has not been of unusual concern for the players or the ATP Medical Services."
"Professional athletes are not immune to illnesses which affect the general public in general," said Gary Windler, medical advisor to the ATP World Tour.
"While we are concerned about and take all injuries and illness seriously, and although some high profile players have suffered from glandular fever in recent years, the incidence of this particular illness amongst our players in general has not been unusually high."
McHale didn't think her tour needed to do more to help players.
"I think we're probably more susceptible to getting it because our bodies are more run down from traveling so much," she said.
"Also sometimes I take a water bottle -- they all look the same -- to the court and all of a sudden I'm like, 'This wasn't my water bottle.' Sometimes it gets transferred like that.
"I know a lot of my friends have gotten it. They're not athletes. For them it wasn't a big issue. It's amplified when you're an athlete."