TOKYO >> Japan’s Empress Michiko, turning 77, says staying healthy is an uphill battle.

As Japan’s empress marked her birthday Thursday, she acknowledged that age has made it more difficult for her and Emperor Akihito, who is also 77, to carry out their official duties.

The popular imperial couple did not travel abroad this year, although they actively reached out to survivors of the March 11 earthquake and tsunami. Akihito delivered an unprecedented TV address to the nation, and the pair visited evacuees for seven straight weeks from the end of March through May.

Michiko suffers from severe pain in her left arm, while Akihito has been on hormone therapy since prostrate surgery eight years ago. He also takes medication to prevent the narrowing of his coronary arteries.