People who don't get enough sleep show higher levels of inflammation, say scientists who study colds. Smoking, chronic stress and lack of exercise can make you more susceptible to the viruses, too. Frederic Cirou/PhotoAlto/Corbis hide caption

itoggle caption Frederic Cirou/PhotoAlto/Corbis

Eat fish or take a fish oil supplement? Research suggests eating fish regularly over a lifetime is good for the brain. But when it comes to staving off cognitive decline in seniors, fish oil supplements just don't cut it, a study finds. iStockphoto hide caption

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Eggs may be more vulnerable to freezing than embryos, but that's just one factor that affects the odds of having a baby with frozen eggs. Jean-Paul Chassenet/Science Source hide caption

itoggle caption Jean-Paul Chassenet/Science Source

Michael Arnott, of Cambridge, Mass., says he used to have trouble staying awake on long drives. Sleep specialists discovered he has obstructive sleep apnea, though not for the most common reasons — he isn't overweight, and doesn't smoke or take sedatives. M. Scott Brauer for NPR hide caption

itoggle caption M. Scott Brauer for NPR

Bacillus subtilis may look like pasta under the microscope, but the bacteria are common in the gut of humans. Could the microbes be contributing to our belly fat? Too soon to tell, scientists say. BSIP/UIG via Getty Images hide caption

itoggle caption BSIP/UIG via Getty Images