Employees working at night are at increased risk of diabetes. A possible mechanism is related to differences in glucose regulation at night. Laboratory simulated night work studies show regulation of blood glucose is impaired at night. Regular exposure to high glucose levels at night may explain the observed relationship between night work and diabetes. We performed a field study of 19 nonsmoking women from the health-care sector to investigate how night work and the composition of meals affect post-prandial blood glucose levels. Blood glucose levels were self-assessed by finger-prick blood sampling using the Beurer blood glucose monitoring system. Measurements were done before and 15, 30, 60, and 120 min after different test meals: a nighttime high sugar meal during a night shift and during a day shift, and a reference (low sugar) meal under these same two conditions. There was a statistically significant difference in blood glucose concentration between the four test meal conditions (P = .0086). Post-meal blood glucose levels following the night-shift meals, compared to following daytime meals, rose faster and remained elevated for longer a duration of time. At the 15 min time point following the high sugar test meal, the blood glucose concentration was 8.3 mmol/L when consumed at night vs. 7.3 mmol/L when consumed during the day. We found no difference in area under the blood glucose concentration–time curve (AUC) after consumption of the high or low sugar test meals during the night shift compared with consumption of them during the day. Our findings indicate the glucose levels in response to food intake by female night working healthcare assistants are higher following the nighttime compared with daytime consumption of a high sugar content meal. However, we did not find a difference in total glucose exposure across time (assessed as AUC) after eating a high vs. low sugar meal during the night shift.

The wireless motility capsule (WMC) technique is a noninvasive and radiation-free method for measuring regional and whole gut transit in response to ingestion of a granola bar (SmartBar) or an eggbeater meal. The WMC has the potential to measure gastrointestinal transit in metabolic research as part of a standardized mixed meal tolerance test. To evaluate gastrointestinal transit with the WMC and postprandial plasma/serum concentrations of metabolites and gastrointestinal hormones as well as subjective appetite following ingestion of a SmartBar compared with a standardized mixed meal. Fourteen healthy participants [3 men, median (IQR) age 53.8 (45.8; 64.50) y, body weight 63.9 (59.9; 69.7) kg, BMI 23.1 (21.8; 23.9) kg/m²] completed a 2-d crossover study. Following ingestion of either a SmartBar (260 kcal, 7 energy percent (E%) fat, 74E% carbohydrate, and 19E% protein) or a standardized mixed meal (498 kcal, 34E% fat, 49E% carbohydrate, and 17E% protein), participants swallowed the WMC. Blood samples were drawn in the fasted state and postprandially for analyses of gastrointestinal hormones and metabolites. The primary outcome was difference in gastric emptying time between the 2 test days. Wilcoxon signed rank tests were used to test differences between test days. Median (IQR) gastric emptying time was 98.0 (70.0; 113.0) min longer (P = 0.001) and incremental area under the curve of triglyceride, glucose-dependent insulinotropic polypeptide, and peptide YY were 40 mmol/L × min, 45.7%, and 63.7% greater after the standardized mixed meal compared with the SmartBar (all P < 0.001). The WMC can be used in combination with a standardized mixed meal for evaluation of gastrointestinal transit in healthy men and women. Gastric emptying time was prolonged in response to the standardized mixed meal whereas transit times of the small bowel, colon, and whole gut did not differ between the test meals.

Background: Night shift work often implies shorter sleep duration and this can lead to sleepiness, which has been associated with an increased risk of accidents and injuries. The aim is to study how the number of consecutive night shifts affects self-reported sleepiness. Participants and methods: The study was a quasi-experimental, within-subject crossover study with 73 police officers. Three work schedules of two, four, and seven consecutive night shifts followed by the same number of recovery days, i.e., days worked or days off, was performed by all participants. Sleepiness was self-reported using the Karolinska sleepiness scale (KSS) every fourth hour on the last night shift and the last recovery day in each sequence. Results: We observed differences in the level of sleepiness between recovery days and night shift days but no differences in the pattern of sleepiness levels on night shift days in the different work schedules. The highest levels of KSS were observed before bedtime (at 07:00 after a night shift and 23:00 on a recovery day). Conclusion: The number of consecutive night shifts did not affect the self-reported levels of self-reported sleepiness among Danish police officers.

Night shift work suppresses excretion of melatonin, but little is known about the needed time for recovery. We aimed to compare levels of 6-sulfatoxy melatonin after three different night shift schedules, including recovery days. In a quasi-experimental, within-subject crossover study, 73 male police officers in Denmark collected morning urine after the last recovery day in three different work schedules with two, four, and seven consecutive night shifts followed by a corresponding number of days for recovery. We found no significant differences for 6‐sulphatoxymelatonin concentrations in morning urine between the three different work schedules indicating similar recovery of melatonin suppression in the studied work schedules.