Though major medical and catastrophic insurance covers immediate health care treatment and hospital stays for those suffering critical illnesses such as heart attacks, strokes and cancer, uncovered medical expenses remain a problem. Expenses such as groceries, mortgages, deductibles, rehabilitation and even travel to and from treatment centers can eat up life savings and credit cards.

According to Colonial Life & Accident Insurance Co., this is where voluntary critical illness insurance plans become helpful. The idea behind voluntary critical insurance is that when someone is diagnosed with a critical illness, benefits are paid directly to the insured, and can be used for nonmedical expenses ranging from out-of-pocket deductibles to paying the electric bill.

Colonial Life claims statistics noted that heart attacks, stroke and coronary artery bypass surgery made up 58 percent of critical illness claims in 2010, with cancer accounting for another 35 percent. Kidney failure and transplants, and other conditions, were responsible for the remaining claims.