"It is not good for the clubs or the national team. England haven't won anything for how many years? Because all the players are exhausted at the end of the season."
While several other top European leagues shut down for the winter, English football has a packed schedule during the festive period.
Van Gaal said the intensity of the top flight made a break even more necessary for the Premier League, which could lose its fourth Champions League qualifying spot to Serie A in 2017-18 due to a lack of recent success.
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"The Premier League is the most difficult league to win because of the high level of the teams. You cannot beat any team easily," said Van Gaal.
"It is a rat race and then you have to play also in the Champions League. It is not so easy and that is why English teams over the last few years have not won the Champions League because of the difference in the leagues."
Van Gaal also said that United, who entertain league leaders City in the Manchester derby on Sunday, could one day be captained by defender Chris Smalling.
"Wayne Rooney is the captain and so you don't have to worry and then Michael Carrick but when they are gone then Chris Smalling can do that," Van Gaal said.
"So I push him also in that situation. Every player makes the steps by himself to improve. I put him in the situation and I help him in the situation and I advise and the player can take it on board or not.
"It is his responsibility."
(Reporting by Shravanth Vijayakumar in Bengaluru; Editing by Peter Rutherford)
