Ever wondered what are the healthiest cities in the U.S.? NerdWallet, a consumer advocacy company based in San Francisco, looked at fifty largest metro areas to find the ones with the best indicators of health, including health scores for the residents, health insurance coverage and a high prevalence of doctors and clean air.

Below is the methodology NerdWallet used to determine the 15 most healthiest cities in the U.S.

1.      How fit are the residents?  We assessed fitness of residents through the American Fitness Index, a composite index that includes the CDC's Selected Metropolitan/Micropolitan Area Risk Trends Behavioral Risk Factor Surveillance System, environmental factors from the Trust for Public Lands, rates of disease and other government data.

2.      Is healthcare accessible?  We incorporated the percentage of residents who have health insurance as well as the number of physicians per 100,000 residents.

3.      Is the air quality good?  Research shows that cleaner air adds an average of 4 months to a resident's life expectancy.  We included the number of high particle pollution days per year for each metro area.