The new year is always particularly busy at gyms as people resolve to put aside their old habits and do more exercise.

But the problem is making that resolve stick, especially on cold days. Extreme sportsman Arda Saatçi says it helps to think forward to the positive buzz and mental health kick you will feel afterward.

"I, too, have a lazybones tendency that I have to overcome every day," says Arda Saatçi, who ran 1,800 miles from Berlin to New York last year.

"But I'm addicted to the feeling I get afterward," the ultra-athlete says. Food tastes better afterward, you generally feel better all around, and you "end the day with a good feeling."

But how do you find the right sport to make sure you do more exercise on a regular basis?

The first thing you should think about is finding out what you enjoy in the first place, says Saatçi, who regularly gives motivational tips to his 500,000 followers on YouTube.

Continuity is the most important thing. "That's also more important than perfection." Many people always strive for the "perfect training plan, the perfect nutrition plan." That's not a mistake, but it can hinder the long term a little, he says.

"Motivation is always relative. The important thing is that you build up a discipline for yourself," says the Berlin ultra-marathon runner.

He recommends not seeing exercise as torture but rather like brushing your teeth, namely "that you cleanse your body, cleanse your mind and do something good for your body."