Arbaje said another problem with seniors is that they tend to have mobility issues, so they may get up for water and urinate less frequently.
But the most important thing for seniors may be ensuring they are cool.
"The No. 1 predictor of an adverse outcome is not having air conditioning," Arbaje said. "Studies show even temperatures in the 70s can be dangerous. It's a real problem for seniors who live alone. Someone needs to be with them or check on them and connect them to services if there is a problem."
That is why city officials are calling and visiting as many seniors as they can during the Code Red alert, which is in effect until Sunday, and urging others to check on their neighbors. There are 11 regular cooling stations open, plus a dozen additional ones. Residents can locate the nearest one by calling311 or going to http://www.baltimorehealth.org/coderedinfo.
Residents having a heat emergency should call 911, officials said.
The excessive heat warnings for all of Maryland east of the Alleghenies were extended through Saturday evening. Baltimore's Code Red Heat Alert was extended through Friday.
Friday's air quality forecast from the Maryland Department of the Environment was for Code Red conditions, with ground-level ozone levels rated unhealthy. Sensitive groups are urged to avoid prolonged exertion, and everyone is advised to limit outdoor exercise.
The cold front on Sunday should drop the daytime highs to the lower 90s, but temperatures will stay in the 90s at least through next Thursday, forecasters said. That would make it 12 days in a row with highs of 90 or higher. The record for Baltimore is 25 days, set from July 12 through Aug. 5, 1995.
As tropical as it was, the weather led organizers to put off Thursday night's planned Afro-Caribbean "Dancing in the Plaza" event at Baltimore's Hopkins Plaza. They hoped to reschedule for a (cooler) date in September.
BGE officials said the region's generators and transmission lines were keeping up with the demand for electricity for fans and air conditioners.
"The system continues to hold up well," said BGE spokeswoman Linda Foy. "At this point it does not appear that we will set a new peak usage record, although we could get close by [Friday]."
On Thursday, Olivia Farrow, a deputy city health commissioner who is in charge of coordinating Code Red days, made about 20 of the 1,065 calls to seniors herself.
"Everyone I called had air conditioning, but they seemed appreciative someone checked," she said.
Meanwhile, in Brooklyn, Pack was still trolling the neighborhood. Outside the community center where she works, she ran into Francis Toporzyski, a 63-year-old who uses a scooter to get around. She gave him some information about handling emergencies and made sure he knew how to call for help.
He said he had air conditioning at home but wanted to get out of the house.
He nodded at Pack, wiped his brow and said, "She's always checking on me."