When Melissa McCann (left) suffered a stroke in 2007, her twin sister, Terry Blanchard, helped her make a full recovery. McCann is now back to work as a flight nurse with Life Flight at the Eastern Maine Medical Center in Bangor. David Wright/Redux Pictures for NPR hide caption

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Reducing dietary salt and alcohol, exercising, not smoking and maintaining a healthy weight are other lifestyle tweaks known to help prevent or reduce high blood pressure, doctors say. David McNew/Getty Images hide caption

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David Oliver sits quietly as he waits for the results of a scan at Ellis Fischel Cancer Center in Columbia, Mo., in 2012. The University of Missouri research professor was diagnosed with cancer in September 2011. He broke the news to colleagues via a video on the Internet. Jeff Roberson/AP hide caption

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Particles of the hepatitis C virus are imaged with an electron microscope. James Cavallini/Science Source hide caption

itoggle caption James Cavallini/Science Source

Otolaryngologist Sandra Lin uses under-the-tongue drops to treat patients with allergies at Johns Hopkins in Baltimore. Courtesy of Keith Weller/Johns Hopkins Medicine hide caption

itoggle caption Courtesy of Keith Weller/Johns Hopkins Medicine

Chick-Fil-A employees Jennifer Cummins, right, and Joshua Figaretti work out in the gym during lunch at the company's corporate headquarters office in Hapeville, Ga. Increasingly employers are offering health plan incentives to encourage healthy behaviors from workers. Ric Feld/AP hide caption

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A micrograph of HeLa cells, derived from cervical cancer cells taken from Henrietta Lacks. Tomasz Szul/Visuals Unlimited, Inc./Getty Images hide caption

itoggle caption Tomasz Szul/Visuals Unlimited, Inc./Getty Images

People who are socially isolated may be at a greater risk of dying sooner, a British study suggests. But do Facebook friends count? How about texting? iStockphoto.com hide caption

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George McCann has been diagnosed with a subtype of bipolar disorder called the "fear of harm" profile, and finds that a prescribed dose of ketamine every few days alleviates his symptoms. Michael Rubenstein for NPR hide caption

itoggle caption Michael Rubenstein for NPR