NEW YORK — Katie Couric is coming back to NBC. This time, she’ll co-host the opening ceremony of the Winter Olympics in Pyeongchang, South Korea. The TV personality will co-host with Mike Tirico, who is replacing Bob Costas as prime-time host of the games, for the Feb. 9 ceremony. The …

Weekend warriors, take a victory lap. People who pack their workouts into one or two sessions a week lower their risk of dying over roughly the next decade nearly as much as people who exercise more often, new research suggests. Even people who get less exercise than recommended have less risk …