Hello Karen! Thank you for using the #asksudrexfeature. The occurrence of cramps or spasms during exercise is quite unpredictable. The simple explanation to cramps is dehydration & loss of electrolytes through sweating. Electrolytes are needed for proper muscle function including contracting & relaxing, any depletion both in the blood & in the muscle can result in uncontrolled muscle contractions commonly called cramps. Try not to exercise in the heat to reduce sweating & fatigue. Always have water or a sports drink with you while exercising & use stretches to gently warm up your muscles before exercise to reduce the incidence of cramping. However, you need to understand that improper muscle warming (both duration and type of movement during warm-up) before exercising is also one of the factors causing muscle cramps during exercise. For muscular pain take Sudrex Joint & Muscle.