Malaysian Prime Minister Mahathir Mohamad has a piece of advice for senior citizens:  They should not be sleeping, but they should keep reading, writing and even quarrelling to keep active physically and mentally.

The 93-year-old Mahathir said that when he quarreled with former prime minister Datuk Seri Najib Razak, his brains were kept active, according to The Star of Malaysia.

“During my retirement, people came to see me, they were not happy with my successor,” he recounted.

“I tried to advise (Najib) but it didn’t work. People kept on asking me to do something.

“I had a big quarrel with the previous PM and my brains were kept active by thinking of ways and means of changing the government,” Mahathir was quoted by The Star as saying.

He was speaking on Saturday at the opening of the Conference on Aging, Learning and Technology: Enriching Lives, Connecting Communities’ in conjunction with The International Day of Older Persons.