Working too hard???

karafortenberry

My sister and I just started working out 4 days ago. We mostly work out on the Wii Fit but we also go to the park and run/walk. Since we started my sister has gotten a few nose bleeds and then I had one today after running in place nearly a mile and a half on my wii fit. We might be working too hard but just wanted to see if anybody else has this problem and knew what caused it or how to prevent it or if you think it even has anything to do with working out? Thanks(: