They say the only certain things in life are death and taxes, but scientists think that might not be true after all. A new study suggests there might not be a limit on how long we can live.

Biologists Bryan G. Hughes and Siegfried Hekimi reached that conclusion after analyzing the lifespans of the longest-living people from America, the United Kingdom, France and Japan.  Their study - which was published in the journal Nature last month - found no evidence of a limit on the human lifespan. If one does exist, Hughes and Hekimi think it has yet to be reached.

"We just don't know what the age limit might be," said Hekimi - a researcher from Canada's McGill University.

So it's not surprising that the average life expectancy in Canada has increased by 22 years over the last century. A newborn Canadian in 1920 could expect to live 60 years. But that average age rose to 76 for Canadians born in 1980, and up to 82 for today's baby Canucks. And it looks like the average life expectancy could continue to rise in the foreseeable future.

"In fact, by extending trend lines, we can show that maximum and average lifespans, could continue to increase far into the foreseeable future," Hekimi says.

So some of us might outlive famous super-centenarians like the late Jeanne Calment of France, who said the secret to living 122 years was eating chocolate. And if nothing else, it gives us an excuse to indulge our cocoa cravings.