A charity bike ride that was supposed to be a one-time fundraiser has turned into an annual tradition that has raised more than $350,000 over the last 20 years.

The John Clark Ride to End Alzheimer’s, to be held this year on Aug. 18, was started in 1999 by Gales Ferry resident John Clark. A longtime seventh grade math teacher at Ledyard Middle School who retired in 2002, Clark said he was a recreational cyclist in the 1990s. After his mother was diagnosed with Alzheimer’s, he decided to do a long-distance charity ride to raise money for the cause.

“I felt guilty that our mother was being cared for by my sister up in Maine and I wasn’t doing much of anything for the cause,” he said, “so I decided as a cyclist I would do a ride to raise funds.”

That ride in 1999 was the tail end of an America by Bicycle cross-country ride, and he rode more than 600 miles from Erie, Pa., to Portsmouth, N.H. He raised $6,600 that year. And though he had planned for his fundraising effort to end there, it was so successful and donors were so supportive, he continued riding to raise money for research.

Since then, Clark has ridden cross-country, along both coasts and along other regional routes to raise money. Some of the more memorable moments included celebrating his 62nd birthday at the top of Monarch Pass in Colorado — he had a banner saying “I’m on top of the hill, not over the hill” — and encountering a bison on the road in South Dakota. He also had one ride cut short prematurely because of the arrival of Hurricane Ivan in New Orleans.

Clark said he’s met and stayed in touch with riders and donors locally and around the country, and his favorite part is raising awareness about Alzheimer’s, including research information from a friend who is a scientist in the field; he said recent investigations are approaching and treating the disease as brain inflammation.

More recently, the charity ride is a 27- or 40-mile route through southeastern Connecticut, starting and ending at the Mystic Cycle Centre. Clark said he starts training in April with 10-mile rides, slowly working up to the full 40 miles.

About 15 riders join every year, a mix of people in his local cycling group, donors and other cycling enthusiasts. While not a race, the routes are designed so all riders reach the I-95 overpass at River Road in Mystic about the same time so everyone can finish through downtown Mystic together.

Clark said the Mystic Cycle Centre hosts weekly rides around the area and is making his ride the “ride of the week” that week.

For the first time, the ride also is posted on the website for the Connecticut chapter of the Alzheimer’s Association, www.alz.org/ct; previously, it was only posted on the ride’s individual website, since it’s a third-party event.

“New research shows exercise combined with other lifestyle factors, including a healthy diet and cognitive and social stimulation, may help reduce the risk of cognitive decline. The John Clark Ride to End Alzheimer’s is a great way to take care of your brain!” Tina Hogan, development manager for the Alzheimer’s Association Connecticut chapter, said in a statement. “We are so thankful for people like John who honor their loved ones they lost to dementia by raising money and helping us help more families.”

At 77, Clark said that anytime he’s asked how much longer he’ll do the ride, he always says he’s aiming for another 20 years on the road, but he wants to see the event continue even after he can’t ride anymore. He said he’s always trying to make the event bigger and better, and he hopes the partnership with the state chapter, and eventually the national organization, will help attract fellow riders and donors.

For more information on the ride or to register, visit alz.org/johnclarkride or write to P.O. Box 574, Gales Ferry, CT 06335.

a.hutchinson@theday.com