RecruitingBehavioural interventionCardiac-Control Affecting Learning Through Mindfulness (CALM)Some types of meditation lead heart rate to become more steady as breathing quiets whereas others lead to large heart rate swings up and down (oscillations) as breathing becomes deeper and slower. The current study is designed to investigate how daily mindfulness practice with heart rate biofeedback during breathing in a pattern that either increases or decreases heart rate oscillation affect attention and memory and blood biomarkers associated with Alzheimer's disease.