Abstract
Body temperature throughout the day. Growth function and chronotype. The self-assesment time of day preference to perform some physical or mental tasks allows to classify individuals as morning-types, evening-types and neither-types. To validate this morningness-eveningness dimension, oral or body temperature has been widely studied. Nevertheless, as there exist large individual differences of temperature within each group, statistical analysis of the temperature curves analyzed hour by hour, revealed no significant differences between groups and most of the studies performed so far have been only able to describe significant differences between extreme groups in the time of the temperature peak. The present study aims a new approximation proposing a growth function to modellize the temperature evolution along the day. This function is characterized by there parameters that explains both the temperature rise and decline. As this function starts measuring the increments from a relative minimum level, subjects of different departure point may be compared. This paper presents evidence showing that the growth function is able to discriminate the thermal evolution of evening-types vs morning and neither types.
