It wasn’t long ago that Oak Bluffs police chief Erik Blake could not imagine riding a bike across town, never mind across the Island, or halfway across the state.

“Let’s put it this way: I wasn’t much of a cyclist,” the chief bluntly remarked last week. “I had the usual mountain bike and I sometimes took it out in the park . . . but it was casual, it was for fun more than anything,” he said.

But during a meeting of the Massachusetts Chiefs of Police Association last August, chief Blake came across a booth for the Pan-Massachusetts Challenge, the nation’s premiere bike-a-thon that raises money for cancer research and treatment at the Dana-Farber Cancer Institute.

Last year more than 5,000 cyclists from 36 states and eight counties raised $35 million to fight cancer; to date the 30-year-old challenge has raised more than $239 million.

Chief Blake was with Hingham police chief Taylor Mills at the time, and the two started talking about what might have seemed, until more recently, a long shot.

“I said to him, ‘You know I’ve always thought about doing this,’ . . . and then I got to thinking,” he said.

Although at the time he might have imagined crossing the finish line, his arms thrust into the air triumphantly as the crowd cheered on the sidelines, there was first the little matter of actually completing the race. Well, not so little, as the two-day race he eventually signed on for was from Sturbridge to Provincetown — a daunting 192 miles.

If the chief’s life were a movie, the next few scenes would likely be a training montage set to the pounding beats of the inspirational song Eye of the Tiger by Survivor. He began waking up at 5 a.m. three days a week to ride his bike around the Island, starting with shorter rides that eventually expanded to 30-mile treks from Oak Bluffs to Edgartown and West Tisbury then back.

Meanwhile his wife bought him a new top-of-the-line Jamis road bicycle, which he has equipped with a computer that measures distances and, more importantly, pace and cadence, which is key when training for an endurance event.

His intense training schedule has had a few unexpected side effects.

For starters, he has a new respect and understanding of Island cyclists in general. For years he heard complaints about bike trails and unsympathetic motorists, but it wasn’t until he experienced it firsthand that it really hit home.

“We were on the road at 5:30 a.m. and this guy in a car shouted [an obscenity] at me, just because I was on the side of the road with my bike . . . afterwards I thought about what exactly I did to [upset] him, and I really couldn’t think of anything,” he said.

The other immediately noticeable side effect is that he lost an eye-catching 70-plus pounds, changing his appearance to the point where people who haven’t seen him for a while don’t immediately recognize him. “It’s the way I looked in my 20s. I was going to the gym to keep in shape, but I really started to see results once I got on the bike,” he said.

And although his training has brought with it personal improvements, his motivation for riding in the challenge is to raise money to help fight cancer. When he hits the road this weekend he will be riding with members of Billy’s Posse, a collection of police officers and family members of police who hope to raise some $50,000 for the Pan Mass Challenge.

The team was named in honor of Southborough police chief William Webber, who lost a nearly two-year battle with pancreatic cancer last year.

Over the past few months, the chief has been busy soliciting donations to make up the minimum $4,200 requirement for all riders. Although the challenge is this weekend, he has until Oct. 1 to continue to raise donations. He technically is not required to complete the race, although he is confident he will.

“I think I can stay in the saddle the whole time. The other guys on my team already explained the emotional aspect of the crowd and the people on the sidelines with the signs. One guy told me about a young kid he saw holding a sign [for the riders] that said: ‘I am five years old because of YOU!’” he said.

The chief said he is already thinking about next year’s Pan Mass Challenge.

“A few months ago if you told me I would be getting up at the crack of dawn three days a week and biking from Oak Bluffs down to Edgartown and then up to West Tisbury and then back, I wouldn’t believe you. But now I love it. I’m really into it,” he said.

The Pan Mass Challenge takes place on August 1 and 2. Islanders Roch Hillenbrand of Edgartown and Phil Robinson of Aquinnah also will be participating in the event. To make a financial contribution to a rider, see onlinepmc.org, or call 800-WE-CYCLE. Checks can be made payable to PMC, 77 Fourth avenue, Needham, MA 02494.