Plasma catecholamines in some airline passengers

Abstract

Assuming that the act of flying may provoke mental stress and increments in plasma catecholamines, in-flight plasma catecholamines were compared in two groups of passengers: a group of ordinary passengers (Group 1, n=15) and a group of passengers who had just completed a cognitive, behavioural treatment programme against flight phobia (Group 2, n=13). No difference in catecholamines was observed between the groups. However, 10 of the subjects in Group 1 and 12 of the subjects in Group 2 had in-flight plasma adrenaline higher than the highest mean +2 SD (above 0.40 nmol/1) of resting plasma adrenaline observed in healthy subjects in a long series of studies previously or simultaneously done in our laboratory. Subjects in Group 2 (n=12) showed an average decrease of 50% from in-flight to post-flight plasma adrenaline. Plasma noradrenaline values were not elevated compared to normal resting levels, but an average reduction of 24% was observed between in-flight and post-flight in Group 2. We could not detect any difference between passengers treated for flight phobia and ordinary passengers. However, in-flight plasma catecholamines, particularly adrenaline, seem to be elevated in some airline passengers of various backgrounds. The most plausible explanation seems to be the discomfort and fear some people feel when flying; however, we cannot exclude that the physiological act of flying per se increased plasma catecholamines. Relatively larger variations in plasma adrenaline compared to noradrenaline may favour the first of these two possible explanations.

Key Words:

• adrenaline
• catecholamines
• flying
• heart rate
• noradrenaline
• phobia
• sympathetic tone