San Francisco, Jul 12 (IANS): Billionaire Elon Musk on Tuesday advised his more than 100 million followers on how to improve their sleep quality that is essential not only for health but also for one's productivity.

Musk said raising the head of the bed by 3-5 centimetres can improve the quality of sleep.

In addition, he asked his followers to avoid eating anything three hours prior to sleeping.

"For improved quality of sleep, raise head of your bed by about 3" or 5cm and don't eat 3 hours before bedtime," Musk wrote on Twitter.

To this American YouTube personality Jimmy Donaldson, better known as MrBeast, asked "anyone want to explain why these two things help to me".

In reply Musk wrote: "Good chance you're experiencing at least mild acid reflux at night, affecting quality sleep without consciousness awareness".

"Ah, interesting. I currently sleep 9 hours a night and I've been trying to get it down without reducing my energy levels/brain function so maybe this will help," Donaldson said.

Last year, in a talk with American podcaster Joe Rogan, Musk said he "works a lot" and sleeps for "about six hours".

The world's richest man said he attends work meetings "until 1 or 2 in the morning" and sometimes also works on weekends. When he slept less than six hours, he found loss in "productivity".

"I tried sleeping less, but then total productivity decreases. I don't find myself wanting more sleep than six [hours]," he said.