How often do you test around sports and activities like swimming? DD does gymnastics and is starting ballet this week. We also go swimming and do other fun summer stuff. I'm checking her before she does the activity, but how often and how long after do I check her. Today she was 83 before we went swimming, so I gave her an apple juice (13 carbs) and some chips that she didn't finish. We went swimming and right after she was 107. We got home, changed and she dropped to 58. I gave her a snack, some strawberries, crackers, cheese and another apple juice and now she is 127. How long after an activity do you usually see an effect or drop and I've heard people talk about drops hours after?