Night / rotating shift work → Insulin resistance (HOMA-IR)
Higher Night / rotating shift work increases Insulin resistance (HOMA-IR).
Four assigned night shifts with a nine-hour sleep opportunity reduced clamp insulin sensitivity about 25 percent in healthy adults. Matched day-shift controls did not move.
Randomized trial · Moderate · N=17
Supported by an experiment or a tightly identified design. Read the caveats.
Mechanism
Bescos, Boden, Jackson, and colleagues assigned a night clock or a day clock in a Victoria University lab. Night sleep sat between 8am and 5pm. Day sleep sat between 10pm and 7am. Both groups had a nine-hour opportunity. Food was each person's usual meals, prepared on site. A 30-minute outdoor walk stood in for the commute. After four night shifts the clamp M value fell about 26 percent. Glucose area under an intravenous test rose about 14 percent. Fasting glucose ticked up. The day-shift group did not show those changes. Muscle Akt and TBC1D4 still answered insulin. Mitochondrial respiration did not move. Melatonin timing and hair-follicle clock genes across the wake period stayed put. The authors read the hit as when people were awake, ate, and slept, not as lost hours or a shifted master clock. Night-shift participants ate more at the first work meal, midnight, than day-shift participants did at 10am. Sleep diaries showed about 25 minutes less sleep on nights, not a significant gap. A later workplace file in professional drivers found higher HOMA-IR on night and early-morning rosters than on days.
Caveats
Bescos assigned the roster. They did not randomize it. They matched groups on age, sex, BMI, and activity so they would not run a crossover with two clamps and two biopsies each. The page label says randomized trial because that is the design class for an assigned schedule. The paper says non-randomised. Clamp pairs were eight night and five day. All eight night-shift clamps were lower afterward. The authors say they lacked power for a between-group contrast after the roster. Seventeen healthy non-shift-workers, mean age 26. Four days. The main paper is available here only as an abstract. The abstract names 17 people. The driver file is a workplace exam, not an assignment. HOMA-IR sat higher on nights and early mornings. Who takes those rosters is still open. Hours in bed are a different page. This page is the clock. Buxton 2012 mixed short sleep with a 28-hour day and lives on the sleep-insulin edge. This is a journal entry, not medical advice and not a reason to change a roster.
Effect
percent_change = 25. Bescos clamp M -25.6±7.4% after 4 assigned night shifts (8 paired); day ns (5). IVGTT glucose AUC +13.7% night. Drivers: higher HOMA-IR on night and early-morning vs day.
Nodes
Named confounders
Cite this page
What Causes What. “Night / rotating shift work → Insulin resistance (HOMA-IR).” https://whatcauseswhat.org/edges/e-shift-insulin (atlas updated 2026-09-02).
Papers
- Four days of simulated shift work reduces insulin sensitivity in humans.
R Bescos, MJ Boden, ML Jackson, AJ Trewin, EC Marin, I Levinger, A Garnham, DS Hiam · 2019 · Acta physiologica (Oxford, England)
- Shift work and insulin resistance (HOMA-IR) among professional drivers.
K Sadeghniiat-Haghighi, F Abbaslou, S Akbar Sharifian, N Izadi · 2022 · Work (Reading, Mass.)