Dr. Adam Friedman, a dermatologist who both treats excessive sweating in patients and has it himself, leaves the hot Dupont Circle Metro station on a Red Line train. (Kery Murakami/Kery Murakami/ Express)

It wasn’t quite as bad as descending into the fires of hell.

But as Adam Friedman began riding down the escalator into the Dupont Circle Metro station during Monday’s afternoon rush hour, he moaned a bit: “It’s been HOT."

The air grew stale and warm as he headed to catch his train home to Bethesda. On his forehead appeared a shine of sweat, which would have been a dripping mess, he said later, if not for medication he takes.

Metro says it’s finally on the verge of replacing the aging pipes that haven’t been able to cool the Dupont or Farragut North stations since they sprang leaks in 2015. Stations rely on a system that pipes water to and from a cooling tower, rather than conventional air conditioning, to lower the air temperature by up to six degrees.

If the work is finished soon, it will finally bring some relief to commuters whose blood has boiled at the slow pace of repairs.

“It’s miserable hot and I am tired of sweating in my work clothes,” complained Meredith Hindley on Twitter on July 16, when Metro was still promising to fix the problem by the end of July. Metro has since pushed back the completion date to mid-August after realizing that lampposts, unmarked in design plans, were blocking the pipes.

But for as much as average Metro riders have suffered, Friedman and some of his patients have it even worse.

They’re among the estimated 15 million Americans with hyperhidrosis, a condition in which the nerves that trigger sweat glands become overactive. There are no statistics on how many Metro riders sweat excessively. But medical researchers estimate about 1 in 20, or 4.8% of Americans, suffer from the illness.

The cause is unknown, but the condition is thought to be hereditary, said Friedman, director of the dermatology residency program at George Washington University’s school of medicine.

Robert Shesser, chairman of the GWU medical school’s emergency medicine department, said in a phone interview that most Metro riders, other than the elderly with several medical conditions, "are robust enough” to handle hot stations.

While sweating buckets can at times cause swelling and skin problems, Friedman said, there’s generally no serious danger.

But for those who have the condition, it can be humiliating and even traumatic — even during D.C. summers, a time when pretty much no one feels fresh.

Some who come to see Friedman avoid socializing when it’s hot because they’re worried about sweating. Others seek treatment for sweaty palms because they’re afraid to shake hands.

“These are things they’re constantly thinking about,” Friedman said.

He can relate. He takes an oral medicine called glycopyrrolate and uses a wipe called QBREXZA, both of which quiet the overactive glands that trigger the sweating. They help but don’t always work, he said.

And worrying about sweating makes him sweat even more. “The embarrassment of holding onto the ceiling bar when I am pitted out makes it even worse,” he said. “Leaving a moist residue on the door I am leaning against is also not fun.”

On Monday morning, Friedman, as he usually does, left for work a half-hour earlier than he otherwise would need to because of the sweating.

When he arrived at Dupont, he climbed the escalator to the street. That’s not how you avoid sweating, he acknowledged. “But it’s about setting priorities,” he said. He had to get to work early so his clothes would have time to dry.

“I don’t want to walk in, to see my first patient, a sweaty mess,” he said.