(CNN) -- Football players in Georgia are hitting the field at night while an ice cream store in Tennessee is hurting for business as people stay inside to avoid the extreme heat that continued to cook the South on Thursday.
Memphis, Tennessee, Fire Department spokesman Wayne Cooke said the majority of its 444 firefighters were making house calls checking on elderly and disabled residents on Thursday.
During their checks, firefighters saw residents sitting outside under shade trees because their homes had become too hot. Cooke said he also saw people mowing their lawn -- an activity that is not advised in extreme heat.
A combination of sweltering temperatures and high humidity could cause heat-related illnesses, the National Weather Service said. The number of suspected heat-related deaths reported by health officials across the South and Midwest in the past week reached at least nine Wednesday as temperatures continued to hit triple digits.
Cooke said the city of Memphis has set up cooling centers and encouraged neighbors to check on each other.
He cautioned people not to rely on fans to keep cool. "They don't prevent heat illness. When it's 90 degrees or above it won't help," he said.
The heat index -- what the temperature feels like when combined with the humidity -- is soaring across much of the South.
CNN Weather's Judson Jones said Thursday's heat indices ranged from 100 to 115 degrees throughout parts of the South and the Northeast. A cold front was expected to cool temperatures slightly Friday in the New England area, but no relief was expected for the South.
On Thursday, Little Rock, Arkansas reached 103 degrees with a heat index of 112, while residents in Jackson, Mississippi, sweated through a heat index of 114.
In Tennessee, even ice cream sales are suffering. John Ellis of Lexington said business has slowed at his family's ice cream store as residents stay home and avoid going out into the heat. Ellis got into his car on Thursday and found the temperature readout to be 122 degrees.
"It was a mistake to get in the car," he said, adding that with the air conditioning running and windows down the gauge still read 110 degrees for a 10-minute trip. "It's almost too hot to even complain," he said.
School has started in parts of Georgia. Cherokee County School District spokesman Mike McGowan said high temperatures are not that unusual for August. One of the high school football teams has moved its practice to the evening, he said, and officials are setting up fans in school gyms that don't have air conditioning. Students are also allowed to bring bottled water on buses, about half of which have air conditioning.
Movies are the fun way to cool off In Oklahoma City, Oklahoma. Starplex Cinemas is offering free movies to senior citizens age 60 and up whenever the temperatures hit 100 through the end of August.
People 65 or older, infants and young children, and those who are already ill are at greater risk for heat-related illnesses.
The Jackson County, Missouri, website offers these tips for staying cool:
-- Avoid liquids containing alcohol or caffeine.
-- Schedule outdoor activities before noon or in the evening.
-- When temperatures reach the 90s, a cool shower can help more than a fan.
-- Wear lightweight, light-colored, loose-fitting clothing, wide-brimmed hats and sunscreen.
-- If you must work in the heat, monitor the condition of co-workers and ask them to do the same for you.