Lifting weights is an effective way to build and strengthen muscles, but it can put a lot of stress on your body, particularly your muscles and blood vessels. While bruises that appear as the result of trauma are understandable, bruises that appear without an obvious cause can be the sign of an underlying medical disorder. If you experience bruising consistently or if you have other symptoms such as joint pain, fatigue or weakness along with the bruising, consult a doctor.
Bruises are caused by broken blood vessels that leak blood into the soft tissue beneath the skin. Although most bruises occur under the skin, they can also occur in the muscle and bone, with bone bruises being the most severe. Bruises to the muscles will usually be accompanied by pain upon movement of the muscle. You may experience pain and swelling along with the bruise. Most bruises clear up after 10 to 14 days after the blood is absorbed back into the body and the vessels heal.
Bruises can be caused by an impact, such as a barbell landing on your chest, but bruises that appear seemingly out of nowhere can be due to a variety of causes. If you have strained the muscle, it is possible that a tear occurred and some blood vessels broke, but you will usually feel pain when a muscle is being torn or strained. Because weightlifting increases blood pressure, the extra strain could break blood vessels weakened by medication, age or an underlying medical disorder such as anemia or high blood pressure. If you have varicose veins, or veins with malfunctioning valves, blood can pool in the vein and burst under the increased pressure experienced during weightlifting.
To help the bruise heal more quickly, wrap ice in a towel or bandage and place it on the bruise for 20 minutes at a time every hour. If you can, keep the bruised area above the level of your heart to reduce pooling of blood. Taking acetaminophen or ibuprofen may help relieve the pain. If you suspect injury is causing the bruise, consult a doctor. If you start to feel a tremendous pressure around the bruise or there are signs of infection, such as a fever or pus in the area of the bruise, seek immediate medical attention.
Experiencing a bruise after lifting weights may just be a sign of muscle strain, particularly if you are just starting a weight-training regimen; however, bruising without obvious sign of trauma is almost always reason for concern, so it's best to consult a doctor. Discuss any medications you are taking, particularly blood thinners, as they are often culprits in unexplained bruises. Your doctor may run tests to check for high blood pressure and anemia, both of which can cause complications if left unchecked. Rarely, bruising without obvious cause will be due to a serious medical disorder such as cancer or hemophilia.