I signed up for "Groove Therapy" with a local dance teacher, Leah Lynn. The youngest in our group is 16, the oldest over 70. Every Saturday, we play out a verb each of us brings to class release, gather, resist, invite " translating abstract intentions into motion. It sounds faintly ridiculous. It is also, disarmingly, effective. Within minutes, something shifts. Stress loosens. Then for the next hour, we learn hip hop shuffles and swing our hips to Kool & the Gang or Beyoncé. I always return home exhausted and exhilarated. The dance classes provoked such a profound shift in my mood as well as my body that I decided to find out if there was more to it. Modern research is now catching up to the fact that dance is medicine, a deeply effective intervention for physical, cognitive and emotional health. Behind the feel-good performance lies hard science. Dance improves cardiovascular fitness, strength and coordination. Dancing activates a wide network: auditory pathways, visual and motor cortex, the amygdala and, above all, the somatosensory cortex and networks that keep track of where your body is in space. A German study that followed older adults in a dance program for more than a year reported increases in gray matter volume and synaptic density in regions important for memory and executive function. [Another study showed] that people who danced more than once a week had a 76 percent lower risk of developing dementia than those who danced less often.