In this study, they considered the impact of higher levels of cardiorespiratory fitness, aka cardio or aerobic exercise, on the gray matter of the brain, the volume of which is linked to many cognitive abilities. In assessing fitness level, the researchers looked at peak oxygen intake. Increases in these indicators were correlated with increased gray matter, and therefore stronger cognitive function. Gray matter is simply one of the forms of brain tissue, and the study found that in cases where the participant had a higher status of cardiorespiratory fitness had an overall higher brain volume.One of the key regions which more gray matter was found was the hippocampus, a portion of the brain associated with both memory and stress regulation. In addition to these functions in a healthy brain, decline in this region is associated with Alzheimer’s, depression, and schizophrenia.According to the Mayo Clinic, 150 minutes of moderate exercise is recommended for good cardiorespiratory fitness. Other components of maintaining good fitness of this kind are healthy eating habits and managing blood sugar, cholesterol, and blood pressure.