Robert Redford was forced to slow down his busy schedule this year (13) after falling sick over Christmas (12).

The veteran actor admits his health deteriorated after weeks of travelling around Europe left him feeling "wiped out" and he fell ill just weeks before he was due to launch his 2013 Sundance Film Festival in Utah in January (13).

He tells Esquire magazine, "I got really sick over Christmas. The temperature went down to 10 degrees and I was skiing, and I was wiped out because I'd been doing stuff in Madrid, in Istanbul. But it'd take that to slow me down."

However, Redford admits slowing his schedule and enjoying the fresh air during his time in Utah helped him recover, adding, "I've been able to carve out spaces for myself. At Sundance, I'm in the mountains - my property is private. I get on a horse and ride for three, four hours. Sometimes five. I get lost."