The 24-year-old helped former club Bayern Munich to the Bundesliga title last term before playing a key role as Germany claimed the World Cup in Brazil.
Kroos has since become a regular feature after joining Real during the close-season and fears he could be heading for burnout if he is not given a rest soon.
"This year I played the entire second half of the season with Bayern," he is quoted as saying by El Pais. "After that I went to the World Cup and, since the Super Cups with Madrid, I have played consistently.
"I have not played more in my life. I'm getting tired.
"To make matters worse, in Spain there is no break in January, like there is in Germany. So I have to get by.
"I guess they will give me a break at some point."