Adult colouring books have become best-sellers. Picture: Pixabay

London - Frazzled parents often hand their children colouring books to keep them quiet - but perhaps they should consider joining in.

Grown-ups who try colouring in feel less stressed and have more energy, research has found. In two separate studies, University of the West of England scientists measured the psychological states of almost 100 adults after colouring in.

They found the activity made participants more awake, energetic, calm and relaxed, and left them feeling nearly twice as contented than when they started.

Study lead author Dr Nicola Holt said: “Colouring in can provide a distraction from stress and anxiety. It makes people very focused.”

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Popular with millions, grown-up colouring books have raced to the top of best-seller lists in recent years.