Developing, maintaining, and USING your muscles goes far beyond vanity metrics. Countless peer-reviewed studies have now revealed that when we use our muscles, it improves the function of our immune system, enhances our cognitive function, and even supports the health and diversity of our microbiome. There really isn’t a facet of health that is not improved and supported by USING our incredible muscular. Here, health psychologist @kellymariemcgonigal shares how exercise improves mental health