some medicines can cause caffeine to stay in your body longer than usual. the kids were getting tired after a 1/2 mile, so we turned around, but we can't wait to explore the trail further on our next visit. what are the things that others do to keep active? when i sit or lay my hips feel like i am a 115 year old woman. try an area with more light or adjusting the distance away from your face that you are holding the phone. 