President Zuma is healthy and continues with his work, he said in an interview posted online.
“In fact my doctors have been saying young people are going to envy you if they knew how healthy you are…I am healthy, and I am working.”
He said people were speculating about his health.
“I read in newspapers about how sick I am and what diseases are in me. I was shocked that that may be another Jacob Zuma, not this one.”
After the May general elections, Zuma was exhausted and doctors had ordered him to take some rest, he said.
“Doctors took a very good decision that I should take it easy, and that is what I have done.”
Last month, Zuma spent a weekend in hospital.
At the time, African National Congress secretary general Gwede Mantashe said Zuma, 72, went for a routine health check and was exhausted from election campaigning.
Deputy President Cyril Ramaphosa stood in for Zuma.
The ANC said its election campaign had been punishing and all senior members of the party would take time off one after another to “re-energise”.
Zuma is currently in Brazil for a Brics summit, and also watched the final of the 2014 Soccer World Cup.