Four people died in the Eastern state of Maryland, one in the Western state of Arizona and another in the central state of Arkansas, according to US media, reported Xinhua news agency.
Mitch Petrus, a 32-year-old American football player died on Thursday from heatstroke after working outdoors in his family's shop.
In Arizona, an air conditioning technician, Steven Bell, died on Thursday while working in an attic, according to local officials.
Temperatures peaked on Saturday in eastern US with many metropolitan regions hitting 38 degrees Celsius, compounded by high humidity.
The heat wave prompted event organizers to cancel their events, such as the New York City Triathlon, which donated its 12 tonnes of prepared refreshments to residents.
In Washington D.C., where a major celebration was held to commemorate the 50th anniversary of Apollo 11's moon landing, emergency vehicles were deployed as locals crowded the national mall after sundown to celebrate.
In a viral post which circulated on social media over the weekend, a police department in the state of Massachusetts appealed to local residents to hold off committing crimes until the heat wave passes.
"Due to the extreme heat, we are asking anyone thinking of doing criminal activity to hold off until Monday," the humorous notice issued by Braintree police said.
( With inputs from IANS )