[Legal time shifting and biologic rhythms: summer hour in question?]

In France daylight saving time is set on last sunday of march (legal time becomes GMT + 2 h instead of GMT + 1h) and set off last sunday of september. Fifteen years ago when it was established this change of time was generally welcomed by the public. Since then strong rejection reflexes have appeared and an association against the summer daylight saving time has been founded. The arguments sustained by the oponents to this system are based on economical, agricultural and/or health considerations. A growing number of individuals claim they cannot withstand the change of legal time and suffer from various troubles mainly fatigue and sleep disturbances. An alteration of biologic rhythms has been put forward by some to explain these troubles. We will here discuss the problems related to the change of legal time and especially those in the field of health. For the latter we will show that troubles when they are present can not ascribed to a desynchronization.