At the Swarthmore Swim Club, children spent the day in the pool as the region remained under extreme heat conditions.
"We just want to keep everyone safe and make sure everyone is having fun," said Ben Burnheter, a lifeguard at the swim club.
Burnheter and other lifeguards stayed under the shade while monitoring swimmers and watching for signs of heat exhaustion and heat stroke.
Paramedics were also preparing for a possible increase in heat-related emergencies.
At Middletown Fire Company, paramedic Kaitlyn Madden said emergency crews were stocked and ready to respond.
"We've had a few people that have been outside that were exposed to the heat that felt faint," Madden said.
She said crews carry extra IVs during heat waves, along with cooling packs and towels used to help people suffering from heat illnesses.
"You can feel lightheaded, dizzy, your heart is beating really fast, you get really sweaty. And then when you get into heat stroke, it's when you get into confusion, pass out, or faint, and that's when it's a true medical emergency," Madden said.
Workers spending long hours outdoors also faced challenging conditions. Quran Williams, who was part of a construction crew laying hot asphalt on Dutton Mill Road in Aston, said staying hydrated is essential.
"I always keep water on me," Williams said.
Williams said the crew hoped to finish its work before the hottest part of the day.
"This is something you never get used to, but you know, it's the benefits, so hopefully we can beat the heat and get out as fast as we can," he said.
Delaware County remained under a 24-hour heat emergency, with about 30 cooling centers open to the public, including libraries. Officials encouraged residents to take precautions and seek relief from the heat when possible.