FORT MYERS, Fla. — Few can understand what it’s like to go through a concussion. They’re difficult to diagnose, even more difficult to gauge. And in a sports world that preaches toughness and pain tolerance, many have a hard time sympathizing with an injury they can’t actually see.

That’s why it can be important for concussion victims to lean on each other for support.

The Mets’ Jason Bay and the Twins’ Justin Morneau — two Canadian-born power hitters fresh off dealing with this enigmatic, dangerous ailment — are two very good examples.

Bay, who didn’t play past late July because of a whiplash-induced concussion, entered Friday’s play 7-for-18 in seven games. he is focused solely on bouncing back from a down year at the plate — not the agonizing headaches that kept him from even watching TV seven months ago.

Morneau, who was limited to only 81 games last season after suffering a concussion while trying to break up a double play, made his spring debut in a “B” game on Tuesday, was scheduled to play in his first Grapefruit League game on Friday, and has felt symptom-free thus far.

Bay has been staying up to date on Morneau’s progress from afar. Before then, he was heavily leaning on him for information and support.

“I’m thrilled for him,” Bay said of Morneau’s recovery. “Having gone through it, he was obviously a lot worse off than I was. I think that for him, [playing in games is] a huge step. And I think more than anything, he wants to be normal. he wants to get back to normal; not just for himself, but for everybody else.”

Before a July 23 collision with a Dodgers Stadium wall, Bay was like most others — he knew very little about concussions. now?

“More than I should,” Bay said.

And so much is left to explore.

Many unknowns

A concussion, defined in simple terms, is the brain rattling against the skull. They frequently don’t come up on MRI or CT scans. the symptoms vary for everyone — Morneau’s biggest problem was a feeling of “fogginess,” while Bay was plagued by constant headaches. And there is no medicine to treat the symptoms. Bay tried using Tylenol, but he found that to be ineffective.

“One of the best ways I’ve heard to describe it,” Morneau said, “is you feel like you’re on an island, because you’re out there by yourself and it’s all based on your symptoms, how you feel.”

For Bay and Morneau, the unknown was the scariest.

When each of them sustained their concussions, the anticipation was that they would return soon. but days turned into weeks, weeks turned into months, and before they knew it, their entire season was gone.

In the initial stages of his recovery, Bay remembers waking up every morning believing it would be the day he was going to stop getting headaches and start getting better.

“And every day,” he recalled, “a letdown.”

With concussions being so puzzling and inconsistent, the best thing to do is immediately visit a doctor, ask lots of questions and talk to others.

Bay and Morneau found comfort in that themselves.

Support from afar

The two never really knew each other while growing up in British Columbia — the fact Bay is three years older probably played a factor — but they became close while playing together for Team Canada in the 2006 World Baseball Classic.

And they got even closer shortly after Bay was diagnosed by the Mets’ training staff with a mild concussion on July 27.

“I basically consulted with him, because he basically had already laid the groundwork,” Bay said. “He paved the way as to what I should be doing.”

At that point, Morneau had been dealing with his concussion for a few weeks. And when he saw the highlights of what caused Bay’s, he immediately thought back to another fellow Canadian and former Twins player — Corey Koskie, who suffered a whiplash-induced concussion that changed the way baseball looked at the injury.

It was Koskie who talked Morneau through his concussion, telling him patience was the most important aspect in the painstaking process. Simultaneously, Morneau relayed the same message to Bay.

“It has its own timetable,” Morneau said. “When it’s healed, it’s healed, and when it’s ready, it’s ready. It’s completely out of your control. as long as you’re doing everything [you should] — getting your sleep, taking care of yourself the proper way and doing all those things — it’s going to be ready whenever it’s going to be ready.”

And before it is, all one can do is wait.

Overcoming boredom, depression

Initially, Bay couldn’t even look at his iPad for more than one minute without having to turn away, with his head throbbing. Walking up steps caused headaches, as did turning on the TV, walking around the house or doing anything that wasn’t sleeping.

So Morneau told Bay to do what he did — lie in bed all day with a cold towel draped on your face.

“I mean, that’s great for a day, for an hour, but at some point, it’s like, ‘I have to do something,’” Bay said. “‘Maybe I can get on my iPad. No, I can’t do that.’”

Doctors — and, yes, both players each heard from several — told Bay and Morneau the only thing they needed to do was relax. but when the mind wanders, relaxation becomes difficult.

Bay found himself constantly pondering his first season in Flushing Meadows, one that began awry with declining power numbers and the Mets’ struggles. Morneau was left to think about the MVP-type season he was having for the Twins, but one he couldn’t finish.

And each of them thought about their concussions.

“That makes it 10 times worse,” Bay said.

“The worst part about it is you have these thoughts, because your mind just gets obsessed with this, because it’s the only thing you can do and the only thing you can think of,” Morneau added. “So you sit there, and your mind kind of takes over, and stress is one of the worst things for helping it heal.”

Methodically coming back

Bay’s concussion happened subtly. he played in the Mets’ following two games and wasn’t diagnosed until he complained to doctors about headaches.

Throughout the entire month of August — every single minute of every single day — Bay would experience mild headaches that he had no way of eliminating. They started diminishing little by little in September. At that point, he was able to watch Mets games on TV, but only a little bit at a time. then, as he slowly climbed the ladder, Bay got to the point when he was able to actually start working out again in October.

But very, very carefully.

“You don’t treat it the right way,” Morneau pointed out, “you deal with those symptoms the rest of your life.”

Morneau should know.

The Twins were very cautious with their slugging first baseman despite being in a pennant race in 2010, and they’re continuing with that approach. Morneau didn’t play until the second week of exhibition contests, when he took part in a “B” game. he was scheduled to play in his first official Grapefruit League game on Thursday, but doctors pushed it back a day, just to be extra careful.

The mentality sure has changed since Morneau’s youth.

The first baseman sustained four head injuries while playing basketball and hockey growing up, but usually just got back out there and kept playing. now, there is a much greater awareness about the injury, and teams are a lot more cautious and conscientious.

Over the past nine years, 50 trips to the Major League disabled list have been a product of concussions, according to FanGraphs.com. Teams now conduct baseline tests for players with traumatic injuries in Spring Training. And this offseason, the associated Press reported that Major League Baseball was considering the idea of a seven-day DL reserved for concussion victims.

But more research, more regulations and more prevention methods are left to be done. for now, Morneau preaches communication — a method that helped him recover.

“Guys have to be honest with how they feel and not be afraid to say how they’re feeling because they think people will look down on them or think they’re not tough or something like that,” Morneau said. “It has nothing to do with that. You can play with a sore elbow or a sore hand, whatever it is. but if you’ve got something wrong with your brain, your reaction time is going to be slower, and your chance for re-injury and long-term damage and everything else is a lot higher.”