Aging generally leads to cognitive decline. As we age, normal processes that help our brains function begin to deteriorate.
For example, one such process is glucose delivery to the brain. Glucose helps provide energy to our brains. As we age, however, our ability to deliver glucose to the brain diminishes. Additionally, aging can lead to decreased activity of an enzyme in the brain called protein phosphatase 2A (PP2A).
Each of these deteriorating processes can lead to an increased amount of tau protein, which are proteins found in the neurons of the central nervous system. Increased amounts of tau protein is called tau hyperphosphorylation.