A group of runners sustained heat-related injuries Saturday morning during a 5k run at Balboa Park.
Authorities received reports of several high school cross country runners requiring medical assistance near Florida Street and Pershing Avenue at around 9 a.m.
They were running in the 68th Annual San Diego State Aztec Invitational.
Authorities said at least 10 runners -- some between the ages of 15 and 17 -- sustained heat-related injuries during the 5k run.
Responders brought ice to the teens and administered aid.
City of San Diego Emergency Medical Services Director Dr. Jim Dunford said at least 10 runners suffering from heat exhaustion were transported to local hospitals to get checked out.
Due to Saturday’s scorching temperatures, authorities recommend San Diegans hydrate and keep cool.
A spokesman for the San Diego Fire Department suggested people avoid any physical activity outdoors today.
"Quite simply the average person shoudn't be out doing anything strenuous in weather conditions like this. Period," SDFD Spokesman Maurice Luque said. "Exercising; hiking; gardening. Don't do it today. Simple."
Luque said the heat wave is particularly dangerous because residents haven't adjusted to the high temperatures that came on suddenly. He said even firefighters are restricting their physical activity today.
The National Weather Service issued a hazardous weather outlook, saying temperatures could reach up to 100 degrees near the beach this weekend.