French President Nicolas Sarkozy is a regular runner
French President Nicolas Sarkozy has been taken to hospital after becoming ill while jogging.
Mr Sarkozy's chief of staff said the president was "doing well" and talking normally with medics at the military hospital, AFP news agency reported.
The 54-year-old president is remaining there overnight for what officials said were "routine" tests.
He was flown to the hospital earlier after suffering what was described as a "minor" nerve complaint.
Mr Sarkozy was taken ill while jogging during a humid afternoon at a weekend retreat at the Chateau of Versailles, outside Paris.
The incident occurred after 45 minutes of "intensive physical exercise", his office said in a statement.
It denied earlier statements that he had lost consciousness. Mr Sarkozy lay down and received immediate treatment from a personal doctor.
He was flown to the Val de Grace hospital by helicopter, where he was later joined by his wife, Carla Bruni-Sarkozy.
A spokesman said he had also summoned aides to his bedside to keep him up to date with world events.
AFP said Mr Sarkozy had suffered a problem relating to his vagal nerve.
It said a condition known as vasovagal syncope could involve a brief loss of consciousness, and changes in the heart rate or blood pressure, especially if the person is dehydrated.
The vagal nerve is a major nerve that runs from the abdomen to the brain and controls many functions.
French member of parliament Patrick Balkany, an ally of Mr Sarkozy, said everything was "going well" and blamed the problem on a diet he said the president was following to lose weight.
"He's fine. He's hungry. He's complaining," he told French radio.
"The president is going to have to take more care, work a little less hard and eat a little bit more," he added.
Mr Sarkozy has cancelled an event on Monday but had not as yet changed his schedule for Tuesday.
The president is regularly seen running and is a keen cyclist.
The Elysee Palace said earlier this month that his last medical examination - on 3 July - showed normal results for cardiovascular and blood tests.
Shortly after his election, his first medical bulletin showed him to be in "good" health.
He campaigned for greater transparency of presidential health bulletins during his presidential campaign, yet a brief hospital stay in late 2007 was not revealed until three months after it happened.
Several French presidents have been accused of glossing over health problems, notably the late Francois Mitterrand, who concealed that he was seriously ill with cancer.