Plasma glucose levels and flight

Background: Noise is able to exert many adverse health effects, ranging from damages on various organs and systems to changes in biochemical and humoral markers. In literature, the effects of chronic exposure to noise on blood glucose levels have been reported, although these results are conflicting: some authors reported hyperglycaemia, others hypoglycaemia and many others recorded no changes in blood glucose levels. Objectives: Considering that the plasma glucose levels are not used as a biomarker of noise exposure, we conducted a pilot study on 6 subjects, 2 females and 4 males, working as clerks in a low noise environment in order to evaluate the possible occurrence of changes on plasma glucose levels in healthy subjects, non-diabetic and not accustomed to flight, exposed to noise and to flight-related stressors. Methods: The subjects completed a specific clinic-anamnestic questionnaire and underwent a general clinical examination. In the first phase of the study, participants underwent blood tests in order to assess the plasma glucose levels at three different times: at 8:00 a.m., on board of a turboprop transport aircraft before the take-off with the engine switched off, after 60 and 120 minutes’ flight. The second phase of the study was carried out one month after the first one and while working in the office; three blood tests were performed again, at fasting and after 60 and 120 minutes. The plasma glucose levels were measured on capillary blood by the refractometry method through the use of Glucoscan One Touch device. Results: The results show an increase of plasma glucose levels during the waiting for the flight and a statistically significant decrease of plasma glucose levels in the first hour of flight (p <0.001), persisting even at the second hour (p <0.001). No significant changes were found in the blood tests performed at work. Discussion: The data show an initial hyperglycaemic response, followed by a persistent and moderate decrease of glycaemia; a similar response was not observed in the same subjects during ordinary work activities. The Authors believe that the initial increase of the plasma glucose levels, recorded in absence of noise on board, could be related to the response to other stressors, such as anxiety linked to the waiting for the flight. The decrease of the plasma glucose levels observed after 60 and 120 minutes’ flight, that is in conditions of prolonged exposure to flight-related stressors and to noise, may be linked to the intervention of several mechanisms: partial phenomenon of adaptation-exhaustion of the neuroendo