WORKPLACE stress has increased in 89 per cent of British workplaces in the past five years, according to a survey by Zovirax, cold sore cream manufacturers. To control stress and stay healthy, stress consultant Dr David Lewis, who helped produce the report, offers some tips: don't try to be perfect don't set impossible targets; escape to a private "paradise" of the imagination; talk over problems with family and friends; laugh a lot; note minor ailments (like cold sores) which indicate that stress is battering your immune system; breathe slowly and deeply at the first signs of stress; and finally, know your "red buttons" - people and events which always make you stressed - and prepare for them in advance.