New Delhi: Extended working hours and high- stress level lead to lack of sleep among employees, thus affecting their performance at workplace, a survey by industry body Assocham has said. The chamber has surveyed people, who are working in sectors like IT/ITeS, telecom, energy and consumer durables, in major cities, including Delhi, Mumbai, Kolkata and Chennai. On the occasion of World Health Day (April 7), it said, 78 per cent of corporate employees feel that they sleep less than 6 hours on a daily basis which lead to fatigue and depression. "Less sleep has wide ranging effects including daytime fatigue, physical discomfort, stress, performance deterioration and increased absenteeism from workplace," Assocham Secretary General D S Rawat said. However, the chamber did not mention about the number of respondents surveyed by it. Among the cities which have reported maximum number of insomnia cases, Delhi ranks first followed by Mumbai, Ahemdabad, Chandigarh, Pune and Chennai, the study said. Further, it said, almost half of respondents said they are also suffering from obesity. The study said it was found that about 40 per cent of corporate employees do not exercise, while others who workout devote less time, it said. The chamber said a dedicated workout regime could prevent lifestyle diseases like diabetes and heart attack.