The Centers for Disease Control and Prevention recommends that adults between the ages of 18 and 64 should participate in muscle-strengthening exercise at least twice a week. Lifting weights, including bench pressing, can satisfy this requirement and enhance your overall health. It's important, however, to bench press correctly, since heavily weighted bench press bars can crack your sternum -- also known as your breastbone -- if you don't handle the bar properly.
According to BodyBuilding.com, you can crack the middle of your sternum or fracture its end, a small projection of bone called the xiphoid process, if you allow the bar to touch your chest too forcefully while you are bench pressing. You can lower the bench press bar to brush your chest or hover just over the top of your ribcage, but moving the bar down so rapidly that it bounces off of you may cause damage.
If you crack your sternum with a bench press bar, there are only two successful treatment options available: painkillers and rest. While nonsteroidal anti-inflammatory drugs like ibuprofen are usually sufficient, some people may need opiates or nerve blocks to control the pain. Damage to the sternum may take several months of no vigorous exercise or bench pressing to heal completely. More serious fractures can require surgery.
The best way to avoid cracking your sternum while bench pressing is to make preventative measures a part of your regular weight-lifting routine. Start with light weights, gradually working up to the heavier ones that may make it more of a struggle for you to control the bench press bar. Always bench press with a spotter that can help you if you get into trouble. The website MuscleMag Fitness advises that you mentally remind yourself to keep the bar off of your body by holding it for two counts right above your chest at the bottom of each repetition.
You may hear a cracking or popping sound coming from your chest when you're bench pressing extremely heavy weights. If the bench press bar isn't touching you, this snapping sound isn't your sternum cracking, but the sound of the joints between the breastbone and the ribs expanding and popping. If you experience swelling and chest pain after hearing this cracking sound, you should use an anti-inflammatory medication and avoid bench pressing until you see your doctor.