The aim of the study was to asses the effect of sleep deprivation during nightshift by monitoring 30 surgeons in unit of surgical gastroenterology in 4 consecutive days. The first day was pre call= day 1, second day was on call= day 2, third day was the first post call day = day 3 and fourth day was the second post call= day 4. The surgeons were monitored in order to asses how performance was on call compared to pre call and post call. The hypothesis was that they would perform worse on call than pre call, and again slightly worse post call.

The surgeons wore an actigraph consecutively on all 4 days, and would fill out a sleep diary on all 4 days as well. The surgeons were heart monitored consecutively on day 1 and 2.

The surgeons were tested in a laparoscopic simulator at 8 a.m. day 1, 4 a.m. day 2, and again at 8 a.m. day 4. At the same given times they would perform the d2 test of attention and prescribe medicine in the Electronic Patient Medication system in accordance with a case they were given. Furthermore they delivered a salivary sample for the determination of salivary cortisol, at the given times.

They sampled urine from 9 pm - 9 am all 4 days, in order to measure the production of melatonin in urine.

The surgeons would fill out the Karolinska sleepiness scale, VAS (Visual Analog Scale) fatigue, VAS sleep quality and VAS general well being at 8 a.m. day 1, 4 a.m. day 2, and again at 8 a.m. day 4. The Karolinska Sleepiness scale was filled out every second hour on day 2 from 4pm - 8 am on day 3.

Inclusion Criteria:

• Surgeons at surgical unit of Gastroenteroloy
• Men and women between the age of 22-50 years.

Exclusion Criteria:

• Pregnancy and breastfeeding
• Endocrine disease, medically treated
• Autoimmune disease, medically treated
• Sleep disturbance, medically treated
• Intake of alcohol within 24 hours before the study and during the entire study

Surgeons at a surgical unit of gastroenterology in Denmark.