To ward off age-related cognitive decline, you may be tempted to turn to brain-training apps. Last year, consumers spent nearly $2 billion on them. Evidence suggests you’d be better off spending more time exercising. The World Health Organization released evidence-based guidelines on reducing risks of cognitive decline and dementia. Although it pointed to some reviews that reported positive effects of brain training, the WHO judged the studies to be of low quality. It said moving your body — at least 150 minutes of moderate physical activity per week, including strength training — is among the most helpful things you can do.

Menopause before 50 linked to heart risks

Reaching menopause before age 50 may increase your chances of developing cardiovascular disease, a study suggests. Researchers found that women who reached menopause when they were 40 to 44 were 40% more likely to have a nonfatal cardiovascular problem, such as angina, a heart attack or stroke, before age 60 than were women who reached menopause at 50 or 51. Reaching menopause at 45 to 49 corresponded to a 17% increased risk. The findings, published in the Lancet: Public Health, are based on data involving 301,438 women.

Study suggests virus causes rare paralysis

Scientists have found the strongest evidence yet that a virus is to blame for a mysterious illness that quickly paralyzes children. Seeking proof of the source of acute flaccid myelitis, researchers checked patients’ spinal fluid for signs the immune system had fought a virus. Sure enough, kids who got sick harbored antibodies that target enteroviruses, the viral family specialists believe is to blame. “This is circumstantial evidence that this is what’s going on, but it’s a powerful piece of circumstantial evidence,” said Dr. Michael Wilson of the University of California, San Francisco.