Chronic moderate-intensity exercise is associated with reduced microglial activation and decreased expression of pro-inflammatory cytokines TNF-α and IL-1β in the hippocampus, with an association to neuroprotection and reduced risk of age-related cognitive decline and neurodegenerative diseases.

When a person exercises regularly at a moderate intensity, their muscles release signaling molecules that calm the immune system throughout the body. These signals reduce inflammation in the blood, which limits how much inflammatory material enters the brain. Inside the brain, immune cells called microglia become less active and stop producing harmful inflammatory chemicals. At the same time, the brain starts making more protective molecules that support nerve cell health. This combination reduces brain inflammation and protects memory circuits from damage.