Starting your own business nearly always means poor pay and terrible hours in the first few months: the toughest boss you ever work for is yourself.

Last week, a survey by research group NOP Financial revealed that 17% of entrepreneurs work between 70 to 100 hours a week in the three months after launching a venture and another 33% work more than 60 hours. By contrast, the EU Working Time Directive Limits the time employees can legally work to just 48 hours a week.

But European legislation has little bearing on entrepreneurs who are prepared to risk their health, relationships and social lives to build a successful business - the key to survival is effective time management.

"It's all about fear; you are pinballing between cashflow, supply, delivery, non-payments of debts, PAYE - and it's impossible to know where you are going to bounce next" says Jonathan Evitt, who works around the clock when his exhibition company is building stands for an event. "You need to have an extremely understanding spouse or partner".

Very long hours can have a serious impact on quality of life, even if the time is spent setting up a business instead of slaving for a big company. Nearly 60% of owner-managers believe working long days affects their health, according to research by the University of Manchester Institute of Science and Technology (Umist).

Some 72% said it damaged their marriage and 73% said it hurt their relationship with their children. More than 75% said their social lives had suffered.

Dino Penge, who launched recruitment Consultancy Bluetel with two partners earlier this year, typifies the entrepreneurial work ethic. He works 13-hour days, six months. "My social life is down to zero and I feel stressed out, but that's what we thrive on" he says.

Entrepreneurs are very often driven by ambition, but the effect of such long hours will be the same as if they are simply bowing to peer pressure generated in a large office.

The line between career and personal life very often becomes blurred when starting a company, but mistaking business for pleasure and relaxation is a common error."The hours are voluntary but they still have a negative impact", says Cary Cooper, Umist's Bupa professor of organisational psychology. "But the upside is that entrepreneurs are in charge so there is less change forced upon them"

Making the most of time spent at the desk is what entrepreneurs should aim for. " learning to work effectively for 50 hours a week could net you the same work output as an ineffective 70-hour week," says Rob Yeung, a business psychologist at human resources Consultancy Nicholson McBride.

The key to maximising productivity is to prioritise tasks and above all, to learn to delegate. Many small business owners are so attached to the company they have created that they find it almost impossible to involve others in its day-to-day running.

Human resources experts recommend simply talking to other people about pressures and problems as a way of putting them into perspective. "Sometimes you can spend hours mulling over a problem, where a quick conversation with someone outside the business - mentor or coach - could give you the perspective or answers you need" observes Yeung.

The next step is to decide what tasks are really vital and what can wait until tomorrow. Many entrepreneurs mistake important jobs for urgent ones and will break up their day to deal with minor issues.

Consider hiring professional help if the workload becomes too great. Owner-managers will take on even specialist functions, such as installing a computer system, believing they cannot afford to recruit more staff.

But if paying a specialist for 20 hours costs less than your own time for 40 hours then it makes financial sense to use an expert.

Finally, striking the right balance between work and leisure is key. Experts recommend taking at least a short break everyday to exercise, read a book or newspaper, or have lunch with friends. Clearing the mind of work issues, even for half an hour, is a good way of getting away from the boss even if the boss is yourself.