The Business School and the Law School will extend their Christmas recesses by one week under fuel conservation plans announced yesterday, in a move that will result in heavier spring schedules for business students and the loss of intersession for their law school counterparts.

Lawrence E. Fouraker, dean of the Faculty of Business Administration, announced yesterday that the recess will run from December 21 through January 14 for most students. However, some special category doctoral candidates will have to return January 9 to take exams, he said.

Allen P. Slaff, assistant dean for administrative operations, said yesterday that classes scheduled during the week of January 7 will be made up during the spring semester.

The Law Faculty decided at a meeting yesterday to extend the school's holiday break through January 14, eliminating a four-day reading period. Exams will run from January 15 to January 21, and the second semester will start the following day, January 22.

Because classes at the Medical School operate under staggered vacation schedules, the calendar there remains unchanged. "It is not feasible to shut down facilities," Henry C. Meadow, associate dean of the Medical School, said yesterday.

Many business students expressed concern last night about the additional workload which faces them in the spring.

A first-year student in McCullough Hall, who declined to be identified, said, "I would rather wear two sweaters and have class in 40-degree rooms than have four cases a day or have classes on Saturday."

At the same time, some students said they doubted whether the missed classes would actually be made up.

"There is an air here that classes won't be made up--that they will just throw the whole thing away and forget about it," said Richard W. Mounce, a second-year student.

"People here are rabid about getting out in time. If we have to go into June to finish classes there may be some controversy," Mounce said.

Law students were divided in their reaction to the calendar shifts, but most expressed dissatisfaction with the decision to cancel intersession.

"Intersession is the only time law students can relax from exams, which are an upsetting and tense experience," said Patti B. Saris '73, a first-year student.

"Christmas vacation is not enough, because when you are not working, you are thinking about work. The new schedule gives us no vacation from being law students," Saris added.

Andrew P. Geoghegan, a second-year law student, said the decision was the best compromise for students who live great distances from Cambridge.

"But this means that people will be studying three weeks during Christmas vacation--not a pleasant thought," Geoghegan said.

The most enthusiastic response to either calendar change came from a second-year business student.

"Maybe you are talking to the wrong person, but as a foreign student I will be happy to go back to Switzerland for three weeks," said Paul E. Abecassis