• Aged 50 years or greater

• Capable of attending screening and assessment sessions and the internet-based intervention modules

• Fluent English speaker

• Corrected (near and far) visual acuity of 20/40 or better

• Adequate hearing for experimental purposes

• Absence of diagnosed terminal illness

• Absence of diagnosed neurological disorders

• No history of psychotic disorder or substance abuse disorder diagnosed by a psychologist or psychiatrist

• Absence of medication use that significantly alters brain activity

• No history of diagnosed learning disability that would interfere with the completion of the cognitive tasks

• Report elevated scores on the self-report Everyday Cognition (E-Cog)-39 subjective cognitive decline with normatively intact performance on cognitive testing (as determined by the neuropsychological battery)

• No evidence of mild cognitive impairment or dementia as assessed by the neuropsychological measures from the National Alzheimer's Coordinating Center (NACC) Uniform Data Set OR inadequate self-reported performance of instrumental activities of daily living

• Ability to engage in light stretching/movement-based activities with or without assistive devices

• Absence of any MRI contraindications

• Not pregnant and not attempting to become pregnant

• Absence of self-reported claustrophobia

• No regular practice of meditation or yoga (defined as once or more per week) AND No previous participation in a structured mindfulness class (e.g., Mindfulness-Based Stress Reduction, intensive meditation retreat)

• Access to internet and at-home computer with a working microphone and video

• Not enrolled in other RCTs examining the efficacy of exercise training, cognitive rehabilitation, stress management, progressive muscle relaxation or other health-based rehabilitation