A new artificial intelligence-powered tool has been developed that uses standard MRI brain scans to estimate the pace of brain aging and predict the risk of dementia years before diagnosis. This brain aging clock, validated across multiple datasets and based on over 50,000 MRI scans, analyzes features such as cortex thickness and grey matter volume to assess memory loss risk, chronic diseases, and mortality. The tool was created using decades of longitudinal study data and offers a practical approach using ordinary hospital imaging rather than advanced futuristic technology. Additionally, research suggests that just 35 minutes of moderate exercise per week can reduce dementia risk by more than 40%. This development highlights the importance of biological age over chronological age in assessing health risks.