Radios in workplaces across the Chinese capital are once more blasting out exercise music this week, as Beijing resumes mandatory calisthenics after a three-year break.

Officials hope as many as 4 million workers will perform the routines at 10am and 3pm each day, although others question how many employers will allow their staff to break from their labours, and how enthusiastic young workers will be about the scheme.

Radio broadcast exercises were first launched in 1951, according to state media. They were suspended in 2007, reportedly so Beijing Sports Radio could devote more time to covering preparations for the 2008 Olympics.

But as China develops, its population is growing increasingly sedentary and in many cases adopting a less nutritious diet, leading to concerns about public health.

Zhang Yujing, a spokesman for the Beijing Federation of Trade Unions, told the Global Times newspaper: "The short-term goal is to involve 60% of the workforces in Beijing by 2011, and 70% of the workforces of the government. We want all state-owned enterprise workers to have restarted this routine by next year."

The newspaper reported that many workplaces declined to take part in the twice-daily, eight-minute sessions yesterday, claiming they lacked the space or time. Even the Beijing Bureau of Sports did not participate, with a spokesman saying most staff were too busy preparing for a martial arts contest later this month.

But many Beijing residents said the move would be good for young people. "They are not lazy, they are just too busy. They have a lot of pressure at work and don't have time to exercise otherwise," said retired engineer Yang Jinrong, 55, as she took a break from playing badminton with her husband in a city centre park.

"Of course, the radio exercises will do young people good. Like they say on TV, 'Life lies in movement'," said Li Zhigang, 50, dropping to the ground to demonstrate the lotus yoga position.

Mr Sun, a 30-year-old who works in marketing, said he hoped private sector firms would adopt the drills. "I think this [resumption] is really necessary, because people's living habits are very bad now. They sit in the office the whole day," he said.

"I have my own exercise plan, but I never put it into practice because I am too busy."