A recent study found that rats that engaged in "chronic" sex (once daily for 14 days) developed more powerful brains. The rats gained a greater number of brain cells and neurons in the hippocampus- a region associated with memory.
Negative stress (such as anxiety) suppresses neuron growth and weakens the hippocampus. So the researchers set out to examine whether sex, a rewarding stressor, also changed the brain.
After male rats had had sex once a day for 14 days, the researchers measured neuron growth, brain cell proliferation, and dendrite complexity in the hippocampus. Rats were then tested for improved functioning with novelty suppressed feeding and an elevated plus maze. They found significant improvements on all fronts.
These findings suggest that sex and other rewarding experiences, reduce anxiety, protect the mind, and improve the brain.
Leuner B, Glasper ER, Gould E (2010) Sexual Experience Promotes Adult Neurogenesis in the Hippocampus Despite an Initial Elevation in Stress Hormones.PLoS ONE 5(7): e11597. doi: 10.1371/journal.pone.0011597