When the mercury rises, so does the number of visitors to infirmaries and emergency rooms.
This summer, 132 people have been treated for heat-related illnesses in the emergency room of Texas Health Harris Methodist Hospital Fort Worth, compared with 86 during the same period last year.
"We are seeing anything from someone passing out while working in the heat to patients who are so severely dehydrated that they are having kidney failure," said Dr. Robert Gullinese, an emergency room doctor at Harris Methodist. "People don't realize how hot it has actually been."
Temperatures reached 102 degrees Tuesday, marking the 18th consecutive day of triple-digit heat in the Metroplex. The hot, dry conditions prompted Tarrant County officials to issue a burn ban. And the heat wave likely isn't over.
Although a heat advisory probably won't be issued for today, the forecast calls for a high of 99 or 100. For the rest of the week and weekend, highs are expected to stay in the 100s.
"It's just hot, and we have been hot for a while," said Dennis Cavanaugh, a meteorologist with the National Weather Service in Fort Worth. "The longer it goes, the more interesting it gets. ... But even if the temperatures only get into the upper 90s, you still have to be careful out there."
For example, at Sunday afternoon's game between the Texas Rangers and Boston Red Sox, at least 40 fans were treated for heat exhaustion, including one child who suffered a seizure and was taken to a hospital.
Rangers spokesman John Blake said the team sought a waiver from Major League Baseball to reschedule the game, but the league declined because of national-television concerns.
Not only has North Texas' heat been miserable, it's been deadly.
In Dallas County, eight deaths have been attributed to the heat this year, compared with three last year, according to a spokeswoman with the Dallas County medical examiner's office.
Tarrant County has had three heat-related deaths this year, compared with one last year and two in 2008, said Linda Anderson, a spokeswoman with the Tarrant County medical examiner's office.
The first death was in May when an 18-month-old apparently slipped out of the house and into a neighbor's car and died of heat exposure. The two others were of adults who had pre-existing conditions and were working outside in June, Anderson said.
But Anderson pointed out that no Tarrant County residents have died of heat exposure during the current triple-digit streak.
"I've been checking every day to see if we have had any heat-related deaths, and we have not, which is surprising," Anderson said. "It's been really hot."
The string of triple-digit days, which started July 31, is tied for seventh place -- with July 2 to July 19, 1978 -- on the list of most consecutive 100-degree days in Dallas-Fort Worth.
The longest streak occurred in 1980: 42 days, starting June 23 and lasting until Aug. 3.
Cavanaugh said some people are probably pulling for more 100-degree days, but most just want cooler weather.
"I guess you have a few that like to see records broken, but I think, for the most part, people will be relieved," he said.
Cavanaugh doubts that North Texas will go through the entire month with triple-digit temperatures since it hasn't happened before -- or at least not in the 120 years that local weather records have been kept.
In the meantime, Gullinese advises people who get dizzy or have blurred vision to take a break. Those who pass out or seem confused should be taken to an emergency room. And everyone, he said, who spends a significant amount of time outside should drink fluids with electrolytes, such as Powerade or Gatorade, in addition to water.
"If you are getting lightheaded and your vision is going dark," he said, "sit down and cool off."
Staff writers Steve Campbell and Nathaniel Jones contributed to this report.
Melody McDonald, 817-390-7386