Manchester United boss says Premier League hampering English clubs in Europe
As United top the Premier League for the first time in almost two years he says English teams are hampered in the Champions League because of the Premier League "rat race".
The continent's elite can play on a Friday and rest before midweek European clashes.
But Van Gaal says there is no such grace for English sides, who have little time for recovery after tough domestic fixtures.
Only Jose Mourinho's Premier League champions Chelsea won their opening Champions League round.
And Van Gaal, ahead of Wednesday's encounter with Wolfsburg, said: "The Premier League is a very difficult league. Every week to beat your opponent is not easy.
"It's always a struggle. A battle. And then you have to also play midweek in the Champions League.
"It takes a lot out of the players. That's why you have to rotate and that's what I'm doing now because I have to protect my players."
Van Gaal also thinks that teams arriving at Old Trafford have no fear factor - they love playing in the Theatre of Dreams instead of dreading it.
He added: "I don't think the players nowadays are impressed by Old Trafford.
"It's fantastic to play for that crowd which is very positive but also for the opponents. It can inspire opposing players."