'The essence of exercise is to do it regularly if it's to have any impact on your health,' Gazeley says. 'And that means five or six times a week.

'I'd waste an awful amount of time going [to an outside gym], and to do that almost every day would be a bit much. At home, I can easily find one hour a day.'

Gazeley spent about $100,000 on equipment and the same on fittings such as mirrored walls and a rubber floor and uses it as often as he expected. 'I'd be pretty pathetic if I had it right there and didn't use it,' he says.

Gazeley was lucky. His house already had a gym, so he merely updated it, installing an elliptical machine for a cardiovascular workout, a multi-gym and a treadmill.

'I went for top-of-the-line equipment and haven't regretted it,' he says. 'With professional kit you can focus on your exercise and not have to worry about it wobbling or breaking down.'

Those without the luxury of a spare room at their disposal can be more creative.

'We have clients converting their bedrooms and living rooms to accommodate a range of Pilates-based reformers and accessories,' says gymnasium equipment provider Kevin Rushton, managing director of Oasis Fitness.

'We've also had an avid climber who installed a boulder wall for practice in his living room.

Rushton says that people are opting for exercise balls and balance devices that can easily be stored, among other small and functional equipment increasingly available for the home.

The physical fitness method Pilates has also become popular in Hong Kong, Rushton says - as reflected in the demand for equipment for use at home and in commercial gyms.

Pilates is compatible with the needs of the ageing population, he says, because movements can be modified to create specific programmes or supplement other training requirements.

It's part of a trend in the fitness industry that has resulted in a proliferation of mind/body programmes that emphasise posture, alignment and core strengths. Yoga has also resulted in a growth in dedicated spaces in homes.

Public relations consultant Esther Ma has what she calls a zen room in her Repulse Bay home where she practises yoga, meditates and works out on a treadmill. Ma used sandstone on the floor and walls, which also accommodate a television and hi-fi equipment.

If space is tight, Italian fitness firm Technogym has designed workout equipment that fits in perfectly.

Technogym's professional quality kit has been displayed in some of the world's most prestigious design shows, including Salone del Mobile in Milan and 100% Design in London. It includes a Spazio Forma folding treadmill ($53,200) that takes up less than one square metre and the Unica multi-gym ($53,300), which provides a total body workout using 25 exercises and takes up less than 1.5 square metres.

The multi-gym also has what's called a virtual personal trainer that monitors your workout and can update your programme online.

'This eliminates the kind of isolation that in the long term affects those who work out at home,' says Alex Chong, region manager for Technogym Asia.

The company has also developed the Kinesis exercise wall, which works all muscles without machinery, using a series of wall-mounted grips, cables and weights - all in about nine metres of wall space. It will be expensive but Chong expects it to be popular.

'The smartest way to fit in a gym at home is to have equipment that occupies minimal space,' he says.

Or you could follow the lead of Gavin Watson, group managing director of a fashion accessories company, who had a gym custom-made to fit in his garden.

It has a pitched roof, aluminium sides, glass sliding doors, a marble floor and air-conditioning. The walls are mirrored (which creates a feeling of space), and it's fitted with Technogym equipment. It cost about $300,000, including equipment.

'The effort required to go to a gym in the morning negated the chance of my actually going,' Watson says. 'It's a considerable investment, but one that pays dividends in terms of well-being.'

Watson says he's well disciplined, and uses his gym every other day. 'I'm self motivated, so working out in my own gym isn't a problem for me,' he says.

'Besides, exercise is all about commitment, and even with a gym membership there are always those who'll put it off until tomorrow.'