My four year old son is amazing! He is so in-tune with his body he can tell you when he is low. If he says "I need a snack" - you better listen and get him something. Today we took off his pump to go swimming (b/s 150). I usually check him every hour. At 45 minute mark he said "I Need a snack." I immediately took him out of the pool and checked - 49! I couldn't believe he was that low and I didn't even see any signs (usually he cries alot when he gets low - but not this time). I totally tell his teachers to PAY ATTENTION if he says he needs a snack. He usually is right. That is great!