One of the best things you can do for breast health is letting your arms swing while walking. So what does swinging the arms have to do with breast health? Zoom in on the picture below and you will notice that many of the lymph nodes are concentrated around the armpits. The lymphatic system is our major line of defense against invaders such as bacteria, viruses, and other pathogens. Lymph can be obstructed by compression of organs, tight muscles, and tight clothing (bras).