A 2007 Decima Research poll found that 79 per cent of Canadians surveyed reported going to work sick at some point in the past year. (CBC)

Determined to get that project done on time, even though your joints have begun to ache and you're feeling a little light-headed? Can't take the chance of staying away from the office because someone might suggest that you're not pulling your load?

Or maybe you're a part-time worker and you don't get paid sick days. And with the economy tanking and jobs disappearing, you don't want the boss to think that you're not totally committed to your job.

If you answer yes, you're probably a practitioner of "presenteeism" — the act of showing up at work or school, even though you probably should be at home getting over whatever it is that ails you.

One study suggested that presenteeism costs the American economy up to $150 billion US a year, as ill workers perform well below their usual levels while they pass on their ailments to their co-workers. A Cornell University study found that presenteeism could account for as much as 61 per cent of the total cost of worker illness — or as little as 18 per cent.

The Cornell study looked at the costs of coming to work with 10 of the most common conditions. Respiratory infections (such as colds and flu) were responsible for 21 per cent of the presenteeism costs, not including the added costs of potentially infecting others. Others considered were allergies, asthma, arthritis, depression and migraines.

In October 2006, Harvard researchers reported that 94 per cent of the people they surveyed said they would stay home, away from other people, for seven days to 10 days if they had pandemic flu and 85 per cent would do so if a household member were sick. Equally high numbers said they would heed calls not to leave their community while pandemic flu circulated.

But one in four adults said there is no one to care for them at home if they got sick — and another one in four said they could not afford to miss work for even a week. One in five said they feared their boss would insist they come to work — even if they were sick and contagious.

A 2007 Decima Research poll found that 79 per cent of Canadians surveyed reported going to work sick at some point in the previous year.

Statistics Canada estimates that by 2005, Canadian workers were calling in sick an average of 9.2 days a year, up from 7.3 days five years earlier. The agency doesn't have figures for people showing up for work when they shouldn't.

The problem goes beyond the general workforce. A study published in the Journal of Internal Medicine in August 2010, found that even health care workers — doctors, nurses, nurse's aids and ambulance workers — were showing up for work when they had flu-like symptoms. In many cases, doctors would go to work with the kind of symptoms that — if a patient reported them —t hey would have told them to stay home.

What symptoms should keep me at home?

• You have a fever of any kind - you could be contagious.
• You're suffering from achy joints.
• You have a persistent cough accompanied by green mucus buildup and a runny nose.
• You have a severe sore throat.
• You are throwing up.
• Your eyes are bright red and have a discharge.

After you've called in sick, it might not be a bad idea to call your doctor.

What symptoms are normally OK to go to work with?

• You are sniffling, but don't have a fever. You could have allergies.
• Your throat tickles or you have postnasal drip.
• Your ear aches.
• You have a sinus infection.
• You have a dry cough with little or no mucus.

If you are recovering and are no longer contagious — and feel up to it — you should be able to go to work, as long as you do your best to avoid contact with others. You should also tell your colleagues that you are getting over an illness, but no longer pose a threat to their good health.

What should I do if my co-worker is exhibiting symptoms, but insists on coming to work?

• Avoid direct contact with your co-worker.
• Do not use their telephone or workstation.
• Wash your hands frequently or use a hand sanitizer.
• See whether you can move to another workstation temporarily.
• Complain to your supervisor.

What can I do to avoid getting sick at work?

Germs love your hands and they'll easily transfer there if you touch a contaminated surface — like a telephone, desk or someone else's hands. People tend to sneeze or cough into their hands. They will eventually touch other things — like your hands.

• If someone has a cold, don't shake hands with him or her or kiss them.
• Wash your hands frequently, employing proper hand washing techniques (plenty of soap and warm water, rubbing your hands together vigorously for at least 20 seconds).
• Avoid surfaces that may be contaminated - such as in washrooms, close to where other people might wash their hands but not quite as well as you do.
• Use a hand sanitizer.
• If you haven't washed your hands or sanitized after touching a surface you're not certain about, avoid touching any part of your face.

Renzo Bertolini of the Canadian Centre for Occupational Health and Safety says it's critical that employers take an active role in trying to curb presenteeism.

"They can come up with policies like offering free flu shots at work," Bertolini told CBCNews.ca. "They should also communicate to their workforce that if you are sick, you should stay home."

Bertolini says a clear policy is an important message to workers that management accepts the fact that people will be away from time to time.

Is there a proper way to sneeze or cough when people are around me?

When you — or someone near your — sneezes or coughs, germs can easily travel about a metre. They could latch on to you or a surface that you might touch later on. They could also bounce off a surface and travel a little farther.

There are some precautions you can take:

• If you're about to sneeze or cough, try to back away from people and cover your mouth and nose.
• No tissue handy? Try sneezing or cough into the crook of your arm and not into your hands. This keeps the hands from carrying germs and passing them on to others.