Study Description

    Effects of sleep duration on glucose tolerance
    What is the purpose of the study?
    In this study, we hope to learn whether blood sugar levels are affected by the amount of sleep that a person gets on the previous night.

    Who can take part in the study?
    Healthy men and women who are 21-30 years old, with a BMI in the range between 18.5 and 27 kg/m2 can take part in the study. You must be a non-smoker with no history of chronic disease. You should not be taking any medications. Women who are pregnant or who have an irregular menstrual cycle are not eligible. To find out if you are eligible, we will ask you to fill out questionnaires that take about 20 to 30 minutes to complete. If you are eligible and willing to participate, you will be invited to take part in the research.

    How long is the study?
    Your involvement will last about 5 days. You need to make 3 study visits to Duke-NUS Medical School/ NUS. The first visit is to provide written informed consent to take part in the study. The second and third visits happen on consecutive mornings. During each of the morning visits, you will spend about 3 hours at Duke-NUS/ NUS to undergo blood sugar testing.

    What happens during the study?
    Over the course of 4 days/nights, we will ask you to keep a sleep-wake schedule that is determined by the investigators. On the first 3 nights, you are required to spend 9 hours of time in bed for sleep each night (from 10:00pm to 7:00am). On the fourth night, you will be randomly assigned to either 9 hours (10:00pm to 7:00am) or 5 hours (2:00am to 7:00am) of time in bed for sleep. During these 4 days, you will be asked to keep a sleep diary and wear an actigraphy watch that is used to monitor your sleep-wake pattern. After the third and fourth nights of sleep monitoring, you will be asked to report to Duke-NUS Medical School / NUS for an oral glucose tolerance test (OGTT). Before each OGTT, you will be required to go without food/beverages (except water) starting from 9:30pm on the previous night (no snacking or breakfast). The OGTT involves a finger-prick test to measure your blood sugar. After your fasting glucose is determined (about 8:30am), you will be asked to finish a sugary drink. A second finger-prick test is performed 2 hours later (about 10:30am). Between finger-prick tests, you will take a series of computer tests to assess your cognitive performance and mood.

    Do I get reimbursed?
    Yes, you will receive $120 if you complete the screening procedures and both study visits. If you decide to quit the study early, there is no penalty and we reimburse you for what you completed.

    Posted on: 5/9/2019
Please email to for more information if you are interested in participating.
© Chronobiology and Sleep Laboratory 2019