Japan is currently the country with the longest life expectancy. However, experts believe that will change by the year 2040.

As scientists and researchers discover more and more advances in medicine and technology, our health and quality of life improve, for the most part anyway. It was only a few centuries ago that anyone over the age of 50 would have likely been one of the oldest in their respective town. Nowadays, most in the developed world probably hope that they live to at least 80.

How long you live often depends on where in the world you are. If you call a developing or third world country home then sadly, your life expectancy probably won't be much higher than it was in places like the UK and the US hundreds of years ago. In fact, a study in the Lancet journal recently revealed that the African nation of Lesotho's life expectancy could drop as low as 45.2 years by 2040.

RELATED: LIFE EXPECTANCY IN THE UK HAS STOPPED RISING FOR THE FIRST TIME EVER

At the other end of the scale, researchers also discovered that Japan will likely be dethroned as the country with the highest life expectancy. Lancet wrote that it's research revealed Japanese people will be expected to live until 85.7 years old by 2040. Spaniards, on the other hand, will have a life expectancy of 85.8 years.

Back to the bad news. The average expected increase in life expectancy between now and 2040 is predicted to be 4.4 years. Not bad. However, if you live in the US, the expected increase is a quarter of that. Over the next 22 years, Lancet predicts Americans will only live an extra 1.1 years. That will see the US drop to 64th in the rankings. Meanwhile, China's life expectancy is expected to rise way above America's to 81.9 years.

The statistics gathered are based on a number of variables such as patterns in diseases like cancer and HIV, as well as alcohol and tobacco consumption in various nations. Although tobacco use is apparently a problem in Spain, the country has a tax-funded healthcare system. That will likely be the main reason it is a full 63 places higher than the US in Lancet's rankings.

READ NEXT: BRAILLE-FRIENDLY SCULPTURE MADE OF NAILS AND SCREWS UNVEILED AT INDIAN ART FESTIVAL