BATCHELDERS GRANT — The heat index soared into the 90s, making for a perfect day for a hike and swim outing for the Denmark Mountain Hikers.

The objective was to climb 2,850-foot Caribou Mountain in the White Mountain National Forest in Oxford County and after, to cool off in the Wild River. But the outing, like others the Denmark Hikers do each Friday, also allowed members to make a spiritual connection in their collective love of nature.

The group was started in 2010 by Denmark Congregational Church Rev. John Patrick and the church’s clerk, Allen Crabtree, as a way to inspire the members of their congregation to achieve better health. They even made up a club patch that states, “Ascendo Ergo Sum,” Latin for: “I climb, therefore I am.”

But almost immediately the Denmark Hikers expanded beyond the small rural church.

Today the group is made up of mostly retirees who live at the foothills of Maine’s western mountains. An average of a dozen hikers take part in the weekly hikes, and often there are more than 20.

At least two members are atheists. Another is a Buddhist. Most do not attend a church of any kind. Patrick welcomes them all.

“So many things in the modern world pull us apart,” Patrick said. “Nature is a great unifier.”

As the group has grown (Crabtree maintains an email list of 300), so has the club’s offerings. The adventures by the Denmark Hikers now include overnight camping trips, backpack expeditions, an annual award ceremony celebrating each hiker’s total miles, and the popular hike-swim outings.

Six hike-swim expeditions are being offered this summer, with the next one taking place Friday at Low’s Bald Spot and the Emerald Pool in Pinkham Notch, New Hampshire.

Some hike-swim outings involve difficult climbs. Others are across historic grounds, such as the Emerald Pool, which was the subject of the famous painting by Albert Bierstadt.

“The Emerald Pool is well known to locals as a wonderful spot to swim on the Peabody River, but it is not listed in guidebooks or most maps. It looks today very much as it is did in 1870 when Bierstadt painted it – so beautiful that it takes your breath away the first time you discover it,” Crabtree said.

The opportunity to soak in warm summer river water or wade in is the reward after a difficult climb.

“I’m the lifeguard,” said Jeff Sturgis, 69, of Minot, a heart-attack survivor who joined the group three years ago.

The hikers carpooled from the Denmark church, the weekly meeting spot, to Caribou Mountain. They fanned out in two groups of seven to climb the Mud Brook Trail, which is steep in places. They hiked more than six miles, waiting for the slower hikers as they went, moving up and over the mountain in six hours.

The mountain’s panoramic views of the Presidential and Mahoosuc ranges reminded Trudy Dunn of Ossipee, New Hampshire, how she met the group five years ago.

“I was on a grubby little mountain in New Hampshire when Allen walked up to me. He had 15 to 20 people with him. This huge amount of people. They all were so happy,” said Dunn, 65. “They stopped, and Allen, as you’ll see him do all the time, takes out this little piece of paper and asks (for) my email (address). And the next thing you know I’m getting these invitations. It was instant, less than a week. And they’ve taken me all around Maine ever since.”

Sturgis is grateful for the Denmark Hikers’ all-welcoming philosophy.

“Religion has nothing to do with it, other than the religion of the outdoors,” Sturgis said. “In my mind, nature is the thing that is all-powerful and inspirational.”

In three weeks he’ll welcome the Denmark Hikers to his camp on Flagstaff Lake, and there they’ll enjoy a few days of hike-swims. And Sturgis will delight in making that possible.

“My wife was not too happy I was hiking alone. This group gives her peace of mind. I’ve been in the best shape I’ve been in for a while,” he said.

After the hike, Mary Glatz, 70, sat in a rushing section of the Wild River, reflecting on how the group has expanded her world. When she first learned of the group in 2015, she thought having to meet at the church, an hour from her Scarborough home, was too far to drive.

But now she gets up at 5 a.m. most Fridays to meet with the Denmark Hikers. And she would have made more than 25 hikes the past year if a shoulder injury had not sidelined her.

“The most difficult hike I did with them was up and over Mount Eisenhower,” Glatz said of the 4,760-foot climb.

“It was frightening. We got up there and the wind was blowing 60 mph. I’ve never been somewhere I couldn’t stand up. People die on mountains like that. It was frightening at the summit. But at the same time it was breathtakingly beautiful. The snow had dusted the trees like powdered sugar. And I thought, ‘If I could do that, I could do anything.’ ”