The day before the Boston Marathon, the weather forecast was predicting an August heat wave in April, with temperatures nudging 90 degrees during the race. Scary!

Maureen Sproul, all trained and ready to race her second Boston, sounded unimpressed. “I don’t care how hot it gets,” she posted on her Facebook profile. “Taking no prisoners.”

Normal people would wring their hands and fuss. Sproul’s fellow tough-minded runners, including Scott Brown, Dave Howard, Laurie Nicholas and Bob Dunfey, just applauded with a chorus of Facebook “likes,” and three dozen commenters mostly pumped their fists with go-go exhortations. One guy did add a “be mindful.” Not Cheryl Bascomb: “Yeah baby! Leave it all on the road. Kill it girl!”

On race day, that’s pretty much what Sproul did, running fearlessly through a furnace that hit 89 degrees 10K into the race, in Framingham, and covering the 26.2 miles from Hopkinton to Boston in 3 hours, 28 minutes and 21 seconds. Her pace averaged 7:57 per mile. And she finished third of 397 finishers in her age group (55-59) after celebrating her 56th birthday five days before the race.

Boston 2012 saw winning times almost 10 minutes slower than last year’s. Watching the fun amid the uproar near the Eliot Hotel about 1K from the finish line, I caught a glimpse of Sproul from behind as she motored into the Massachusetts Avenue underpass. She was moving well, as were plenty of runners, but not all. Some walked, some paused and bent over to gather themselves in woozy contemplation, and one guy sat on the grass for some minutes with his legs stuck straight out before him and his back against a signpost. Now and then a siren sounded and a cart speeded by with a runner strapped on.

Sproul had aimed to run under 3:20 — her lifetime PR in 14 marathons is a 3:09 back at the Pine Tree Marathon in 1991 — but decided to go by feel. She started in the third corral of the second wave.

“I usually run better in the heat than most people, as long as I can get completely drenched,” Sproul said on Friday. “I wet my hair before the race and keep hitting the water tables — it was great that so many people set up tables in addition to the BAA’s.

“I just kept rotating, drinking water and pouring it on myself. People were passing out bags of ice, so I’d put one down my jog bra or under my hat. That was nice, because it would last a while.”

Sub-3:20 was not out of reach — Sproul hit the halfway mark in 1:40 and change — but it was not a day for a negative split. She slowed a bit in the Newton hills, and a bit more in the later miles when she had to weave through people clogging water tables or walking or wobbling. And though she “felt great” by Friday, she did not escape Boston unscathed. Her feet were scorched by the pavement, and she had them treated with ice bags in the medical tent after the race.

Sproul was well-trained for Boston. She gets boot-camp workouts at UNUM, where she’s an underwriting specialist, and since Jan. 1 she’s hit a week’s high of 78 miles; had seven 20-mile training runs; and raced four half marathons including the new Midcoast Half, at Lincolnville (1:36), plus the Midwinter Classic 10-Miler (1:13:52).

So like many runners who in Boston’s heat couldn’t fully capitalize on their fitness, she’s already looking to her next marathon, Sugarloaf, on May 20. And New York City in the fall.

And she’s focused on the Mt. Washington Road Race on June 16, training for which includes not only hill work near home in New Gloucester but also early-morning softer-surface hill repeats at Lost Valley. Most of the time she does the Lost Valley climbs solo. (“Once in a while I talk someone into coming along, but they don’t come back for a second session.”)

Sproul ran 1:34:40 at Mt. Washington in 2011, and this year would like to break her PR of 1:34 at her seventh “Run To The Clouds.” Not many people set lifetime PRs at age 56. But she’s already conquered the heat. Age may well be next.

John Rolfe of Portland is a staff writer and a road runner. He can be reached at 791-6429 or at: [email protected]