Adults should exercise for at least 150 minutes per week. A new study published in the journal PLOS ONE suggests that less than half of mothers exercise that much. UK researchers analyzed data from almost 850 women between the ages of 20 and 34. They found that women with school-aged children averaged about 26 minutes of moderate-to-vigorous physical activity per day. Mothers with more than one child got 21 minutes per day. And mothers with children 4 years old or younger only got about 18 minutes per day. While there is no doubt that children make it difficult to find free time to exercise, research suggests that regular physical activity can help parents cope with the daily challenges of being a parent.