Armstrong, Kerry, Brown ride in cancer fund-raiser

“Every water stop, we spent a good 10, 15 minutes at each one,’’ Brown said.

This year’s 32d annual fund-raiser was a star-studded event, which organizers hope will raise $34 million toward cancer research. Armstrong, who is among the world’s most widely known cancer survivors, joined the senators, each of whom has participated in the fund-raiser before.

About 5,300 participants, 350 of them cancer survivors, cycled along various routes through Massachusetts on the first leg of the two-day event. Today’s bicyclists will face the challenge of periodic heavy rains, according to the National Weather Service’s forecast.

Between Brown and Kerry, the two hope to raise $100,000.

But reporters at the finish were mostly interested to hear them talk about the country’s downgraded credit rating and yesterday’s downing of a helicopter in Afghanistan that left 30 Americans dead, 22 of them Navy SEALs.

Each expressed heartbreak at the news of the crash and anger about weeks of economic anxiety.

Of Standard & Poor’s decision to reduce the US credit rating Friday, Brown said, “It doesn’t surprise me.’’ Separately, a visibly frustrated Kerry said, “The institution [of the Congress] isn’t the problem; it’s the people in it.’’

Kerry later told the Globe in the phone interview that “it’s easier to raise money for the Pan-Mass Challenge than it is to raise the debt ceiling.’’

Armstrong won the difficult Tour de France cycling competition seven consecutive times - all of them after having overcome testicular cancer that spread to his lungs and brain. He retired in February, saying he wanted to spend more time with his family and focus on his campaign against cancer.

He was in Nantucket this week on vacation with his girlfriend and four of his five children and joined the Pan-Massachusetts Challenge this weekend for the first time.

“In the old days, [111 miles] would have been like a walk in the park,’’ Armstrong said yesterday. “I don’t know about now.’’

Kerry waged a successful battle against prostate cancer; his wife, Teresa Heinz Kerry, is being treated for breast cancer. It was Kerry’s ninth time riding in the Pan-Massachusetts Challenge.

“We’ve made progress’’ in cancer research, Kerry said. “One of the things that I keep harping on is we have to advance treatment, we have to advance cures.’’

Brown said he was riding for Salem District Court Judge Samuel Zoll, who died of cancer this year. Brown said the fund-raiser was a good chance to meet interesting people, but he insisted that he is not campaigning.

“While others are in election mode, I’m in problem-solving mode,’’ Brown said.

Wendy Maeda of the Globe staff contributed reporting. Ben Wolford can be reached at bwolford@globe.com.