Some women have changes in their period because they exercise too much. You may need to make your workouts less intense, or exercise less often. If stress is the problem, learning how to manage your stress -- and possibly also talking with a counselor -- may be helpful. Extreme changes in your weight can affect your periods. Weight gain can make it harder for your body to ovulate, so weight loss could help with that. But extreme, sudden weight loss can also lead to infrequent or irregular periods.