Family caregivers of adults with Alzheimer’s disease and related dementias (ADRD) are the fastest growing group of informal healthcare providers in the United States. These individuals experience high levels of stress and physical and psychosocial symptoms related to their caregiving role. We provided 20 ADRD caregivers (≥ 55 years of age) with training and access to a mobile health app for at-home practice of gentle yoga and yoga breathing exercises. Here, we report secondary outcomes, including changes in caregiver physical and mental function, burden, fatigue, sleep, and biological stress markers (salivary cortisol and 1,5-anhydroglucitol [1,5-AG] assays) from Baseline (Week 1) to Study End (Week 12). Self-reported questionnaire data were collected online via the Research Electronic Data Capture system, and biomarker data were collected via saliva samples. Results supported indications for slight improvement in outcomes of caregiving burden among ADRD caregivers using the gentle yoga and yoga breathing app. Furthermore, slight improvements in mental health were observed; the greatest gains were made by those reporting higher burden and having family members with more severe dementias. Findings indicate that those experiencing the greatest improvement in caregiver burden scores spent the most time doing gentle yoga and yoga breathing exercises. Salivary stress biomarkers moved in a favorable direction (decreased cortisol; increased 1,5-AG) among caregivers practicing the exercises most often. This is among the first studies of gentle yoga and yoga breathing exercises for relieving ADRD caregiver burden and the first we are aware of to incorporate stress biomarker measurement.