For those unaccustomed to the demands of the Premier League, life in the English top-flight can be something of an eye-opener.
There are, as the old cliché goes, no easy games and no winter break in which to recharge the batteries and rest tired legs.
For arrivals from continental Europe, this comes as something of a culture shock.
Arsenal defender Per Mertesacker admits he initially found the going tough, with an experienced international performer struggling to get to grips with how physically draining the hectic festive schedule can be.
He told the Daily Mirror: “The winter break makes you relax, you can switch off. The first year I was here, I almost collapsed in January. It does make you tired.”
The World Cup-winning German centre-half is, however, about to enter his fourth winter in north London and admits he could not be happier in his current surroundings.
He added: “As a German coming to London, I was impressed by the respect I received at Arsenal straight away.
“I am an open-minded and tolerant guy, I enjoy the discipline and structure of life in Germany and I have to say it is different here. But I like it!”
Mertesacker was snapped up by Arsene Wenger from Werder Bremen in August 2011.
Doubts were raised early on as to his ability to adjust his game to meet a Premier League challenge.
He has, however, emerged as key performer for the Gunners over the years, with his towering presence at the heart of the back four seeing him achieve cult hero status at Emirates Stadium.