There are several potential health risks associated with participation in physical activity. The most likely risk is the possibility of muscular-skeletal injury. Typically, these injuries involve minor muscle soreness in previously sedentary individuals who exercise without caution and are associated with overuse or abrupt changes in exercise routine (Stone, 1987). There is a very small risk of cardiovascular incident (such as heart attack, stroke, or death) during aerobic exercise. However, the risk of a cardiovascular event during exercise has only been demonstrated for individuals with established coronary artery disease and risk factors, cardiac rhythm disturbances, or other serious medical conditions (Stone, 1987). Furthermore, the risk of serious medical complications is most persistently associated with very high-intensity exertion in high-risk individuals with infrequent exercise habits (Eichner, 1983). It is worth noting that several studies have concluded that individuals who exercise regularly reduce their overall morbidity and mortality risk and that sedentary people are at much greater risk for disease and/or death at rest than healthy people during exercise (Eichner, 1983; American Medical Association, 1984). To further minimize the risk of injury during exercise, the following safety measures should be applied:

• Don't exercise with an unstable medical condition, healing injury, or uncontrolled disease.
• Contact a doctor if chest pain or pressure, trouble breathing or shortness of breath, lightheadedness or dizziness, or nausea is experienced.
• Do not perform activities that cause sharp pain or aggravate a medical condition.
• Soreness is to be expected in the muscles following any unaccustomed exercise program. Use soreness as a guide for intensity. If the muscles are very sore the day after exercising, exercise at a lower intensity next time. If the pain persists more than 2 hours after exercise, a doctor should be contacted.
• Joint pain should be avoided. The saying, "No pain, no gain", is not true for older adults.