How many steps do you really need to take to be healthy?

In a word, more. A new study of more than 4,800 people age 40 and older did find a correlation between those who took more steps per day (12,000 is better than 8,000, which is better than 4,000) and those who were less likely to die over the course of 10 years. But there was no magic number. Much of the previous research on steps has looked at elderly people or people with chronic, debilitating conditions. With our phones and fitness trackers tallying steps, the researchers wanted to offer guidance on what works. To their surprise, intensity of stepping didn’t matter. “The main thing is to get moving for better overall health as we age," said co-author Eric Shiroma.

Corrections: An item in yesterday’s newsletter misstated the number of foreign doctors who might not receive visas to start their medical residencies in the U.S. this summer. More than 4,200 doctors might be affected by the State Department's temporary halt to issuing visas. And an item in Monday's edition on hiding an antigen on the surface of red blood cells incorrectly described an experiment. The researchers cloaked RhD-positive blood cells to infuse in mice with RhD-negative cells.