Impairments in glycemic control during Eastbound transatlantic travel in healthy adults

Study objectives: Repeated bouts of circadian misalignment impair glucose tolerance. However, whether circadian misalignment associated with travel and jet lag impair glucose homeostasis in a free-living population is not known. The goal of the present study was to examine glycemic control during one week of Eastbound transatlantic travel in healthy men and women.

Methods: Seven healthy participants (5 women; age: 35.6 ± 2.5 years, BMI: 23.9 ± 2.4 m/kg²) traveled from Colorado, USA (GMT-7) to Europe (GMT and GMT+1) and wore a continuous glucose monitor (Freestyle Libre Pro) for 8-14 days before, during, and after travel. Indices of glycemic control were summarized over 24-hour periods and by day and night.

Results: Mean glucose, peak glucose, and time spent in hyperglycemia increased linearly throughout the travel period relative to baseline levels. Mean glucose concentrations rose 1.03 mg/dL (95% CI: 0.34, 1.74) and duration of hyperglycemia increased by 17 min (95% CI: 5.5, 28.6) each 24-hour period. Increases in 24-hour glucose were primarily driven by increases in daytime parameters with rising mean glucose (0.72 mg/dL per day, [95% CI: -0.1, 1.5]) and duration of hyperglycemia (13.2 min per day [95% CI: 4.3, 22.1]). Mean glucose, but not peak glucose or time spent in hyperglycemia, increased each night (0.7 mg/dL per night [95% CI: 0.2, 1.2]).

Conclusions: Eastbound transatlantic travel induced a progressive worsening of glucose metrics during 24-hour, day, and night periods. Future research on managing glycemic control during jet lag in people with metabolic disorders is warranted.

Clinical trial registration: None.