Chinese-style square dancing is running circles around other hobbies for the elderly, with millions taking to parks and plazas across China, swivelling their hips and rolling their arms - but it's not to everyone's liking.

Every evening through the year, hundreds of grannies gather on a large square outside the Master Centre in west Beijing to dance with their instructor, who puts them through the motions of side steps and rotations to help them keep fit and, in the bitter winters, to keep warm.

‘There are several benefits,’ said Yan Fuzhi, 71, who has been dancing on the square for five years. ‘First off, it helps me lose weight. Secondly, it's good for my health and it gets rid of bad habits...

‘I used to sit watching TV, which is bad for my heart and causes high blood pressure. But I'm really happy when I dance, listening to the music, chatting and laughing. All my problems go away.’

But it's that music, pop from the present and decades ago blasted out of tinny speakers, that is the problem for many residents, who complain they can't get to sleep at night because of the racket. But the grannies have nowhere else to go.

‘There are definitely objections against square dancing. Some people don't like dancing and see it as a disturbance,’ said 78-year-old Zhang Lianmeng.

‘I think our country should encourage it as long as they can make appropriate arrangements and make sure they do it in appropriate places.’

Instructor Fan Tiemin, 55, said his group was the biggest in Beijing, with around 500 dancers each evening - sometimes more than a thousand, depending on the weather. Xinhua news agency said more than 100 million were involved nationwide.

‘They don't have much to do, now their children are grown up,’ he said. ‘...They are facing diseases like high blood pressure, high cholesterol and high blood sugar. So they need the exercise.’

Du Peng, a professor at Renmin University and Director of the Institute of Gerontology, said China had made great strides in looking after the elderly, with improved pensions and insurance schemes.

‘But a third area is the spiritual and cultural life of the elderly,’ he said. ‘Square dancing is a part of it. That is, when your basic living standard has been met, especially for those who are healthy, what people most need is fulfilment.’