High-radon soil, gray winters, humid summers and a lot of private wells.
Indiana's biggest risk to your body is one you cannot see or smell: radon. Most counties sit on soil with high radon potential, and the state estimates nearly one home in three is over the action level. Add short winter days with weak sun, ticks in the woods, nitrate risk in rural wells and humid summer heat. One thing that is not on the list: a special Indiana magnesium problem.
EPA places 57 of Indiana's 92 counties in Zone 1, its highest radon-potential category, and no county in the lowest zone. The Indiana Department of Health estimates nearly 1 in 3 Indiana homes has radon above 4 pCi/L, and high readings turn up in every part of the state. Radon is the leading cause of lung cancer in people who do not smoke. A test kit is cheap and is the only way to know your own number.
Indiana sits at about 38 to 42 degrees north. A classic study found that winter sun in Boston, at 42 degrees north, made no vitamin D in skin from November through February, while sun at 34 degrees north still did. Northern Indiana is close to Boston's latitude, and the rest of the state is not far south of it. Add cloudy days and time indoors, and many Hoosiers get little vitamin D from the sun for several months a year, so food sources matter more.
Lyme disease is the most commonly reported tick-borne illness in Indiana, spread by the blacklegged tick. Lone star ticks, common across the Midwest and South, carry ehrlichiosis and are linked to alpha-gal syndrome, a red-meat allergy. Indiana's Lyme rate is far lower than in the Northeast, but a tick usually has to stay attached for a day or more to pass Lyme on, so a daily check after time outdoors makes a real difference.
Many rural Hoosiers drink from private wells, which no state or federal agency tests for you. In farm country, nitrate from fertilizer, manure and failing septic systems can seep into groundwater. High nitrate is most dangerous for babies under six months and during pregnancy. The Indiana Department of Health advises testing well water every year for bacteria and nitrate, and every few years for arsenic, lead and other metals.
Indiana summers are humid, and humidity makes heat harder on the body because sweat evaporates more slowly. The heat index, not the thermometer, tells you how hard your body is working to cool off. The same hot, still days tend to bring ground-level ozone, which irritates airways and can worsen asthma. Check the air quality forecast before a long run or yard work in July.
You may have heard that Hoosiers run low on magnesium. We looked, and found no evidence of an Indiana-specific shortfall. Low intake is a US-wide pattern: national survey data show about 48 percent of Americans get less magnesium from food than they need. If anything, much of Indiana has hard water, and hard water carries dissolved magnesium and calcium, so your tap may add a little. The fix is the same as anywhere in the country: nuts, seeds, beans, whole grains and leafy greens.
If a radon test reads 4 pCi/L or higher, call the Indiana radon hotline (1-800-272-9723) for a list of licensed mitigators. See a doctor for a spreading rash, fever or joint pain in the weeks after a tick bite, or for hives or stomach upset a few hours after eating red meat. If your well tests high for nitrate, do not use it to mix infant formula.