You'll also build muscle to fill out your arms and firm them up. “Generally, when people are complaining about underarm jiggle, they’re usually referring to the area that is governed by the tricep,” says Williams. “If the jiggle or looseness in that part of your arm is due to a lack of muscle, then strengthening and building muscle in your tricep will also create some change in the aesthetic of that area.” She recommends performing triceps push-ups, extensions, and dips to hone in on that area and add some muscular definition to your arms.
From fortifying your immune system against future cancers to reducing the risk of breast cancer, regular exercise helps protect your body. (12) Although researchers aren’t entirely sure how exercise boosts immunity, theories range from bacteria being flushed out of the body to a reduction in stress-released hormones that might increase the risk of illness. (13)