To earn the achievement, you must close all three Activity rings each day for seven consecutive days in January. The new challenge also includes special stickers in iMessages.
Apple offered a similar challenge for 2017.
Back in November, the 2017 Thanksgiving Day Challenge was awarded to anyone who recorded at least 5K (3.1 miles) through a run, walk, or wheelchair workout on the U.S. holiday. Similar challenges are offered throughout the year.