05/16/2013 10:13 EDT | Updated 07/16/2013 05:12 EDT

Chris Hadfield's week: from commanding the space station, to being unfit to drive a car

LONGUEUIL, Que. - Until a few days ago, Canadian astronaut Chris Hadfield was responsible for making sure the International Space Station stayed on course.

Now that he's back on Earth, he can't even drive a car for the next few weeks.

It's been an intense adjustment period for the 53-year-old astronaut who described Thursday how, after months of floating in weightlessness, he's suddenly grappling with the painful effects of gravity.

"Right after I landed, I could feel the weight of my lips and tongue and I had to change how I was talking," Hadfield told reporters during a video news conference from Houston.

"I hadn't realized that I learned to talk with a weightless tongue."

The latest health update by Raffi Kuyumjian, his flight surgeon, said Thursday that the three-time space visitor was starting to show noticeable improvement in his walk and equilibrium.

But Hadfield was not ready to put the pedal to the metal. Kuyumjian said it usually takes about three weeks before a returning astronaut can drive a car again.

When Hadfield spoke to reporters, he said his body felt confused and banged-up by the effects of gravity after his long duration visit.

He said he had to make a conscious effort to keep his head aloft. That he was dizzy. And because the callouses were gone from his feet, his footsteps felt like walking on hot coals.

A first trip to the gym was excruciating, he said, because it felt like two people had jumped on him when he was trying to move on a mat.

Things were so different in space.

''My body was quite happy living in space without gravity,'' he said.

"(It's) a very empowering environment where you can touch the wall and do somersaults, where you can move a refrigerator around with your fingertips and never worry about which way was up.

''Well, that all changed when our Soyuz (capsule) slammed back into the Earth. And my body is catching up with the change. And so the symptoms are dizziness. It's like when you come off a ride at the CNE or something.''

Hadfield returned to Earth on Monday night and was flown to Houston to be reunited with his wife and to undergo tests and debriefings.

Hadfield also announced that his use of social media, which earned him an international audience, won't end with his return to Earth.

He had 20,000 Twitter followers when he blasted off with Russian space colleague Roman Romanenko and NASA astronaut Tom Marshburn on Dec. 19, 2012. This week back on terra firma, Hadfield was hovering around one million followers.

Hadfield said the point of using social media was not to gain fame — but to teach people about space exploration.

"It is just too good an experience to keep to yourself," he said. "And the more people that see it and understand it, the more the benefits of space exploration will roll back into daily life for all of us."

Hadfield added that it felt rewarding to receive a message from someone who said he didn't even know Canada had a space program, until he saw Hadfield's tweets.

There were major changes at the Canadian Space Agency while Hadfield was gone.

While Hadfield was circling the globe every 92 minutes, Steve MacLean quit as head of the space agency and was replaced earlier this year by interim boss Gilles Leclerc.

But Hadfield wouldn't say if he was eager to take over the top job at Canada's space agency.

"I'm nowhere near even thinking about that yet," said Hadfield, who is Canada's oldest active astronaut, when asked if he wanted to be the next CSA president.

"Ask me again in a few months. For now, I'm still trying to stand up straight and I have to sit down in the shower so I don't faint and fall down."