If you exercise all month, you will help your body keep from having cramps. Light exercise during your period will help to ease the heavy, bloated (puffy) feeling. Workouts that stretch your body are best.
Here are a few exercises that are great for relieving cramps: Sit on the floor, legs as far apart as you can get them. Hold your toes if you can, or clasp your ankles lightly. Keep your back straight and breathe in, holding your diaphragm (the muscle under your ribs) up and in. Holding this position, take a few deep breaths. As you breathe out for the last time, bend forward towards the floor and exhale. Sit with your knees open and bent at the sides, with the soles of your feet together in front of your crotch. Clasp your hands under your toes, or hold your ankles. Press the soles of your feet together and breathe in, deeply expanding your chest and lifting your diaphragm, as described above. Raise your head a little, and feel your stomach expand. Breathe in and out deeply into your stomach four or five times. Lie on your back with one leg stretched out, and pull the other knee up to your chin. Clasp your knee with your arms to ease the strain and then hold the posture, relaxing for a few minutes.
If you get pain all of a sudden or notice a change in your periods, you should contact a doctor.
Read about exercise cramps and learn helpful tips for dealing with your period from BeingGirl.