The former England manager said the lack of a mid-season break in the Premier meant the English players were tired by comparison with their rivals in other leagues.
Asked why England had struggled to challenge for honours, Capello said in an interview on fifa.com: "Because they're tired [going into tournaments].
"They're the least fresh of any of the competing national sides, because their league doesn't have a break.
"It's like when you're driving a car: if you stop halfway to put fuel in then you'll definitely get where you want to go, but if you don't then there's always the chance you'll be running on empty before you reach your goal.
"In my opinion the football played in the first half of the English season is much better than in the second half. And because of that, if you want to be a competitive team in the Premier League, you need a really big squad, which is a luxury you don't get with the national team."
Capello, who is now coach of the Russia national side, insisted his time with England had gone well.
He added: "I think it went very well, but it could have gone even better. The way we went out [of South Africa 2010] against Germany still hurts. That aside, I feel satisfied.
"I arrived after the team had missed out on qualifying for Euro 2008, but under me we easily made it through two qualifying campaigns. My win record was very good and I also gave loads of young players a chance, such as Danny Welbeck, Jack Wilshere, Phil Jones, Ashley Young, James Milner and Joe Hart. Theo Walcott had already played a game for England but he established himself under me. I feel I left a good legacy."
Earlier this week, Premier League chief executive Richard Scudamore said his organisation was not to blame for England's failings.
England boss Roy Hodgson was furious with the Premier League when he discovered big matches are scheduled the weekend before England play vital World Cup qualifiers against Moldova and Ukraine, which take place at the beginning of September.
But Scudamore said: "We have not won the World Cup since 1966. The Premier League didn't start until 1992. What happened between 1966 and 1992? Whose fault was that?"
"It seems to me that if England don't win something it is someone else's fault.
"Let's run the reverse argument. Where does that leave the people at the FA in terms of their accountability?
"It frustrates me enormously because it is so palpably not true. It cannot be our fault on any level."