Pitching coach Steve McCatty, catcher Jesus Flores and Stephen Strasburg conference on the mound during the third inning. Strasburg labored through 67 pitches, four walks and three earned runs before being pulled. (Kevin C. Cox/Getty Images)

The record-setting heat blazed down on Turner Field and Washington Nationals ace Stephen Strasburg on Saturday afternoon. He had done everything he could to prepare, lugging a bag full of water to his hotel room the night before. He sneaked back into the air-conditioned clubhouse between innings. It couldn’t prevent the hottest game in Nationals history from taking its toll on one of the game’s best pitchers.

On the mound, Strasburg was dizzy. He breathed heavily. His speech wasn’t right. After he batted in the top of the fourth inning, he returned to the dugout, his face pale. Once Manager Davey Johnson saw that, he pulled Strasburg, who was suffering from dehydration, after three uncomfortable innings in a 7-5 loss to the Atlanta Braves.

“It was pretty scary,” Johnson said.

Strasburg knew Saturday, with a temperature of 104 degrees at game time, would be brutal. Other Nationals players adjusted, too, chugging Pedialyte. Shortstop Ian Desmond opted for a sleeveless shirt under his uniform and adjusted his socks to help with the heat.

“Obviously I want to go out there and compete and I expected a lot more of myself,” Strasburg said. “By no means was I going out there thinking I wasn’t prepared for it. I did everything I could to be ready for it as far as hydrating and everything.”

But Saturday wasn’t just hot, it was borderline unbearable. With a high temperature of 106 degrees, it was the hottest day in this city’s history. Yet 26,491 brave souls sat in the stands for the game.

From the start, there were signs Strasburg wasn’t himself. He labored against the very first batters of the game, walking Michael Bourn and Martin Prado. He threw deliberately and slowly walked around the mound between pitches. One of the hardest throwers in the majors hit only 95 mph on the scoreboard radar gun. Sweat collected on his forearms and neck. By the second inning, his shirt and pants were soaked.

Strasburg exited the first inning unscathed thanks to two strikeouts and a flyout. He also escaped the second inning without issue. But in the dugout, Strasburg wasn’t speaking with pitching coach Steve McCatty like he normally does. Standing in the tunnel that connects the dugout to the clubhouse, Strasburg was breathing heavily. Catcher Jesus Flores came out to the mound to calm him down.

“ ‘Hey, breathe. Take your time. Just trust yourself,’ ” Flores said he told his pitcher. “But I knew at the same time, the weather wasn’t easy to handle.”

In the third inning, Strasburg unraveled. He walked consecutive batters with one out, missing with his usually explosive fastball. Right fielder Jason Heyward took an outside pitch and smacked it the opposite way into left field for a run-scoring double. First baseman Freddie Freeman drove in another run with a sacrifice fly to deep center field. Then Strasburg’s worst nightmare strode to the plate: second baseman Dan Uggla.

Hitting a measly .235, Uggla seemed like no sort of threat. Strasburg had struck him out in his first at-bat on fastball. But Uggla has proved to be one of the few hitters to get to Strasburg, going 6 for 11 with two home runs in his career off him before Saturday.

Uggla took a change-up from Strasburg for a ball. He drilled the second pitch over the head of novice left fielder Tyler Moore for a run-scoring double and a 3-2 lead. Strasburg, watching from in front of the pitcher’s mound, didn’t even look upset. He looked plain beat. He took off his cap and wiped his forehead on his sleeve as he stepped back onto the mound. He had allowed three runs on only 67 pitches.

Despite his struggles, Strasburg was prepared to continue pitching and Johnson had every intention of letting him do so. Strasburg came to the plate with two outs and the bases empty in the top of the fourth inning, the back of his shirt drenched. Though he seemingly had little intention of swinging, Braves starter Mike Minor walked him. After that half-inning ended, Johnson emerged from the dugout, signaling for reliever Chien-Ming Wang. It matched the shortest outing of Strasburg’s career.

“A lot of us get a little light-headed sometimes in the heat,” Johnson said. “He’s such a gifted athlete I thought I’d see how he went out and threw the ball at warmup, but when he came back in he was white as a sheet.”

After he left, Strasburg received three IVs of saline fluid. His blood pressure finally stabilized. Team doctors and trainers will continue to monitor Strasburg, Johnson said, but he is expected to fully recover in time for his next start.

“It was kind of tough for a lot of us, but none of us were working as hard as Stras,” he said.

Wang, upon replacing Strasburg, had problems unrelated to the heat. Wang, who has been working to fix a hitch in his throwing mechanics, allowed four runs on five hits over two innings, turning a 3-2 deficit to 7-2.

The Nationals (44-32) narrowed the gap in the sixth inning. Minor had withstood the heat to that point, allowing only two runs. But LaRoche drew a walk and Desmond collected his 23rd double of the season, chasing Minor from the game. Consecutive singles by Moore and Flores off reliever Kris Medlen made the score 7-4.

The Nationals cut the deficit again in the seventh when LaRoche smacked his second double of the game, scoring Michael Morse. Desmond and Moore then drew walks to load the bases. But Flores grounded out to end the threat. The Nationals wouldn’t score again.

Following the game, Strasburg said he was feeling better. He naturally sweats more than most people, so he prepared as much as he could for the heat. But the ultra-competitive Strasburg couldn’t come to grips with how his body had responded.

“It’s tough,” he said. “I feel like I let the team down today. It’s just something I’ve got to get over.”