People who do regular fitness training are less likely to suffer stress, according to a leading fitness authority.

Exercise stimulates brain chemicals called neurotransmitters which many people believe mediate moods and emotions, relieving stress, says the American Council on Exercise (ACE), a leading US fitness authority.

Physical activity can also reduce anxiety, and is prescribed in clinical settings to help treat nervous tension, ACE continues.

"Following a session of exercise, clinicians have measured a decrease in electrical activity of tensed muscles," a spokesperson said.

"People have been less jittery and hyperactive after an exercise session."

Those prone to stress and anxiety might benefit from weekly fitness training sessions, which would also help to improve general health.

ACE believes that exercise can encourage people to eat better, as those who exercise regularly tend to eat more nutritious food - therefore assisting with weight loss.

Jenny Edwards of the International Stress Management Association states that "stress in itself isn't an illness but it causes, exacerbates and contributes to illnesses".