The Working Time Regulations (WTR) gave effect to the European Union Working Time Directive (WTD), which was originally adopted in 1993 as a health and safety measure. The HSE says that poorly designed shift-working arrangements and long working hours that do not balance the demands of work with time for rest and recovery can result in fatigue, accidents, injuries and ill health. And the TUC says there is a significant body of evidence that shift work, and in particular night work, can lead to cardiovascular problems, obesity, diabetes and breast cancer. Shift work is also linked to stomach problems and ulcers, depression, and an increased risk of injury.