Here, experts debunk some of the scariest but usually harmless symptoms with tips on when they may warrant concern.
Stretching, reaching or simply walking can trigger snaps, crackles and pops from a knee, shoulder or from your back. All that noise may sound scary, but it’s usually nothing to worry about, says Jessica Matthews, an exercise physiologist with the American Council on Exercise. In fact, it may simply be gas. Specifically, fluid in your joints (which acts as a lubricant) contains dissolved gases such as oxygen, carbon dioxide and nitrogen. “Pressure changes within the joint causes these bubbles to burst within the fluid, creating a cracking or popping sound,” says Matthews. Tendons shifting out of place as the joint moves and arthritis can also cause a popping sound. See a doctor if pain or swelling accompanies the sounds.
Running for miles in shoes that fit poorly can cause toes to bump up against the top of your shoe, making the toenail turn a frightening shade of black. It may look morbid, but “runner’s toe” is simply the result of the skin underneath the nail bruising and bleeding, says Matthews. “This causes the blood to pool under the nail with every stride. It’s usually harmless but can be very painful.” Avoid it by getting shoes properly fitted. Matthews suggests getting fitted for shoes at the end of the day, when feet are largest. See a doctor if pain, swelling and redness appear, which may be signs of an infection.