Athletes have long known about the natural "high" that exercise can induce. Now, for the first time, medical researchers have demonstrated that exercise can also reverse the effects in the brain of psychological trauma experienced early in life. Exercise can ease anxiety and depression-like behaviours induced by an adverse early-life environment, reports the journal Psychoneuroendocrinology. It does so by altering the chemical composition in the hippocampus - the part of the brain that regulates stress response, say researchers from University of New South Wales. "What's exciting about this is that we are able to reverse a behavioural deficit that was caused by a traumatic event early in life, simply through exercise," said Margaret Morris, New South Wales' pharmacology professor. The findings, derived from studies on lab rats, are further evidence of the plasticity of the brain and its ability to re-map neural (nerve and brain cell) networks, according to a New South Wales release. Previous studies from University of New South Wales' School of Medical Sciences have shown that comfort eating - eating palatable food rich in fat and sugar - achieves similar results. With many neurological (nerve cell related) diseases originating in early life, researchers believe the results could provide clues for novel ways to tackle a range of mood and behaviour disorders. Morris is New South Wales' pharmacology professor, who will present the findings this week at the International Congress of Obesity in Stockholm.