BOSTON (AP) — Former Boston Symphony Orchestra music director Seiji Ozawa has canceled planned appearances at Tanglewood this summer on the advice of his doctor.

The 80-year-old Ozawa had two scheduled appearances at the western Massachusetts venue in July, his first there in a decade.

But the orchestra said in a statement Thursday that following two periods of heavy work in Europe and Japan recently, Ozawa developed a fever which resulted in weight loss and a weakened immune system.

The statement said "Ozawa has decided to follow his doctors' advice and during the next few months primarily focus on recovering his physical strength."

Ozawa said the decision made him "very, very sad and sorry," and he is concentrating on eating and gaining more body strength before returning.