For years, health experts have been focused on one number when it comes to evaluating the health of a community: life expectancy. Life expectancy is a good indicator of things like the quality of health care systems, the financial stability of a community, and the availability of healthy foods. But new research has emerged that has some experts looking toward a different set of numbers to measure human health: healthy life expectancy. In other words, the number of years that you will spend not just living, but living a life free of disease and disability.

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According to research from the University of Washington's Institute for Health Metrics and Evaluation (IHME), life expectancy is on the rise in many countries around the world. From 1990 to 2013, researchers found that global life expectancy rose in all but 11 of the 188 countries surveyed.

That sounds like good news until you hear that healthy life expectancy has not followed the same pattern. So people are living longer, but they're spending those extra years saddled with illness. The gap is greatest in Switzerland at 12.8 years, where life expectancy is 82.7 but healthy life expectancy is only 69.9. The gap is narrowest at six years in Papua New Guinea where life expectancy is only 59.8 but healthy life expectancy is 53.8.

The point is that while we have all had our eye on the end game, paying attention only to the number of years lived, we've forgotten that it's also important for those years to be healthy.

"The increase in healthy life expectancy has not been as dramatic as the growth of life expectancy, and as a result, people are living more years with illness and disability," the study's authors explained.

In the U.S., the difference between life expectancy and healthy life expectancy is 11.7 years. We have a life expectancy of 78.9 years but a healthy life expectancy of only 67.2 years.

The biggest factors that affect a person's health and quality of life are heart disease, respiratory infection, stroke, and back and neck pain.

The study highlights the need to focus on things like diet, physical activity and stress management so that we can not only add more years to our lives, but also add more life to them.