Spain lies far to the west of Europe, with most of its territory geographically in the same zone as neighbouring Portugal and Britain.
But, with the exception of the Canary Islands in the Atlantic, Spain operates in the same time zone as France and Germany, one hour ahead of Greenwich Mean Time in winter and two hours ahead in summer.
Spain has been in the same time zone as central Europe since 1942, when Francisco Franco's fascist government adopted it in line with Nazi Germany.
"The fact that Spain for more than 71 years has not been in the correct time zone causes us to get up too early and sleep on average one hour less than the time recommended by the World Health Organisation," said a report presented to parliament on Thursday.
"This negatively affects productivity, causing absences from work, stress, accidents and school drop-outs," the report by a parliamentary committee added.
It recommended various measures, including "evaluating the cost and consequences of returning to the western European time zone which was in force in Spain before 1942".
It said the time zone discrepancy explained why Spaniards tend to eat, leave work and go to bed later than their European neighbours.
"Our timetable is determined more by the sun than by the clock. We eat at one o'clock in the afternoon and dine at eight, according to the sun, but the clock says it is three o'clock and 10 o'clock," the text said.
Shifting the time zone would give Spain "more time for the family, for training, for personal life and leisure and would avoid wasted time during the workday," the report said.
"The results would bring us into line with Europe in many respects in which we currently differ, particularly in productivity and competitiveness, in having a balanced family life and in sharing family duties."