Exercise above their determined heart rate range

Jumping into the sauna or hot tub immediately following a workout.The temperatures of saunas and hot tubs can be detrimental to a body that already has an elevated temperature and blood vessels dilated from activity. Your body needs to dissipate heat in order to bring your heart rate back to a resting zone and re-circulate blood back to your organs. High temperatures in hot tubs and saunas will cause lightheadedness, dizziness, fatigue, nausea or worse -- heat exhaustion, heat stroke and heart attacks. Instead, try a cool shower or allow your heart rate to return to resting levels before getting into the saunas and tubs.
3. Holding your breath while lifting weights. Holding one's breath during weightlifting increases blood pressure significantly, possibly leading to lightheadedness, dizziness, nausea, hernia, heart attack or stroke. To avoid creating high internal pressures, inhale and exhale with each exercise phase of a repetition and breath naturally during cardiovascular activity.
4. Not having a physical prior to beginning an exercise program. You want to have the most benefit with the least amount of risk; it would never be wrong for you to get a complete check up prior to beginning activity -- especially if you are older than 45 or have other risk factors like smoking, hypertension, high cholesterol or a positive family history. If you have two of the above criteria, you are considered to be at risk for heart disease, diabetes or stroke. While exercise is the best thing for your condition, beginning a program without the proper guidelines can do you more harm than good.
5. Exercising above their determined heart rate range. Continually pushing your heart rates to the maximal limits during your cardiovascular workouts is overstressing your heart and lungs unnecessarily. When your heart rate is up to maximal loads, there is a greater chance for irregular heart rhythms. You do not need to place such high demands on your heart to see cardiovascular benefits or to burn fat.
6. Using hand or ankle weights while walking or during aerobic classes. Many fitness guidelines indicate that the use of hand weights during the aerobic portion of step training produces little if any increase in energy expenditure or muscle strength. The risk of injury to shoulder joints is significantly increased when weights are rapidly moved through a larger range of motion. It is recommended that hand weights be reserved for strength training, where speed of the movement can be controlled. In addition to shoulder injuries, ankle weights on the arms increase heart rate significantly and can lead to cardiovascular complications in less fit individuals.
7. Wearing head phones when exercising outside. The beat from your favorite musician or the intrigue of the latest audio book may keep your interest during an outdoor exercise session, but your awareness is diminished and the risk of twisting your ankle or getting hit by a car is increased. Besides, studies show that although music or entertainment may help you to exercise longer, your intensity is not as high.
8. Not listening to your body. Abnormal heart beats, pain, chest pressure, dizziness or insomnia following intensive exercise are signs of an over-trained body that may be at high risk for a heart attack and injury. Take a hint: slow down the pace or reduce the number of routines. It would be advisable to have a medical professional assess your condition if you experience any of the major warning signs of cardiac distress during an exercise session. If any symptoms persist during or following an exercise session, have your signs evaluated.