11/09/2014 06:53 EST | Updated 01/09/2015 05:59 EST

The Best Defence Against Colds and Flu Is More Sleep

According to the Public Health Agency of Canada's FluWatch Canada has once again entered the cold and flu season. The expected exponential growth in cases has begun and soon will lead to widespread coverage of the country with a combination of coughs, sneezes and sick days. Also, as expected, in response to the rise, the public is being bombarded with messages on how to best protect against these viral infections.

As with every year, the most common health product offered is the flu shot. But while this will protect against influenzaviruses, it will do nothing to stop the plethora of other non-vaccine preventable respiratory viruses such as adenovirus, coronavirus, enterovirus, parainfluenzavirus, metapneumovirus, rhinovirus, and respiratory syncytial virus. As a result, other interventions continue to be offered including immune boosters, vitamins and minerals, probiotics, netty pots, and of course the never ending list of hygiene products including hand sanitizers and wipes.

But amidst all the efforts, one very successful means to stay healthy has been largely ignored: sleep. Although this daily activity may not seem to be related to these infectious diseases, several decades of research have shown those forty winks may also help to prevent those sickly sniffles.

Back in the 1980s, the effects of sleep deprivation on the human body was examined. The results revealed when normal sleep patterns are affected, the immune system tended to weaken. Further investigations discovered the most affected response mechanisms were those required to fight off viral infections.

By the turn of the millennium, the mechanism was fully elucidated; the effects were due to a disturbance in the interaction between the neurological system and immunity. Worse, this was a gradual process in that long term disturbances could not only impair proper immune function but also render the body with the inability to fight a viral invader. But while the molecular and cellular possibilities were known, no one really knew if this actually meant more infections in those lacking some good shuteye.

The first studies linking sleep and respiratory viruses came in the early 1990s when researchers began to question whether psychological stress had any impact on the chances of catching the common cold. The results revealed just how much impact pressure has on the body; those who suffered the most mentally also were most likely to become infected.

The findings were repeated based on similarly related questions. Were stressful life events more likely to lead to infections? Yes. How about an overall negative attitude? Again, yes. What about socioeconomic status? Absolutely. When researchers looked at all these variables, one common denominator was found. No matter what the cause of the stress, the symptom all experienced was a lack of being able to get a good night's rest.

In 2010, the definitive link was established as sleep habits were compared with susceptibility to one of the common cold viruses, rhinovirus. For two weeks prior to an experimental infection with the virus (done under proper ethical approval), people were asked about their sleeping habits and the quality of their moments of slumber. At the end of the 14 days, the brave volunteers were given an infectious dose.

Over the coming days, some came down with full infection; some were only mildly affected and some had little to no illness. Comparing these levels of infection to the amount of sleep attained revealed a definite correlation between slumber and resistance to infection. Those who had less than seven hours were almost three times more likely to come down with an infection than those who had eight or more hours.

Due to the established link between the neural-immune interaction and susceptibility to respiratory infection, the number of studies into the effects of sleep deprivation have grown significantly. For the most part, the focus has been on the development of inflammation and its associated illnesses.

In 2012, a group of researchers identified sleep disturbances as a risk factor in the autoimmune skin condition psoriasis. In the same year, another team looked at the effects of slumber on heart health. The onset of inflammation due to deprivation meant a higher risk for problems. Perhaps the boldest move happened earlier this year when a UCLA researcher suggested spending a good eight hours in bed is a critical part of staying young.

Studies to unveil the marvels of our daily hibernation -- and the deleterious effects of deprivation -- will continue and many more discoveries will be made. In the meantime, as the cold and flu season continues to spread in Canada, we should take heed from the research suggesting slumber is critical to health. Although vaccination and other means are effective and worth following, we can all rest assured some of the best proof to prevention is not in a pill but on a pillow.