Seasonal characteristics of external respiration pattern in students with different chronotypes

The objective of the paper is to analyze the external respiration pattern in students with morning, afternoon and evening types of activity at rest and after monotonous mental work load during the day in the spring-summer and autumn-winter seasons. Materials and Methods. The authors examined three chronotypes: eveningness with a delayed sleep period (owls), morningness with an advanced sleep period (larks) and indifferent or asynchronous chronotype (pigeons). The individual chronotype was determined using Horne and Ostberg morningness-eveningness questionnaire in Putilov's modification and Moskovchenko questionnaire. In the morning, afternoon and evening spirography was used to record external respiration in the normal condition and after monotonous mental load. Changes in the volume and time spirogram parameters were analyzed. Results. It was found out that "pigeons" and "larks" demonstrated more evident seasonal and daily external respiration dynamics if compared to "owls"...