The purpose of this study is to determine the effects of light on the timing of the body clock. This research will help in the development of methods to improve sleep, as well as daytime alertness and performance of people your age. In order to evaluate this relationship very carefully and completely, you will be asked to keep careful records of your sleep and daily activities, and spend a total of 7 days and nights in our laboratory, where you will provide some saliva samples and may sit in front of a bright light box.

This study is 14 days long. If you successfully complete the study, you will receive $925. There will be two other young adults participating in the study at the same time as you. The study is separated into 2 parts, a "home sleep week" (7 days) and a "lab week" (7 days). Below we describe what procedures occur throughout the study. Then, we describe what will occur during the home sleep week and the lab week.

Throughout the duration of the study:

  • You will wear a wrist monitor, which looks like a wrist watch. It will record movements, and tell us when you are awake and when you are asleep.

  • You will be required to communicate with the lab daily with your bed and wake times. Because the study requires frequent contact, it is important that you have a phone and internet access to use while in the study.

  • You may wear a necklace with a small (1-inch by 1-inch) light sensor attached throughout the duration of the study; it looks like a medallion. You will need to make sure that the light sensor is always facing out and on the outside of your clothes and coat.

  • You will be required to keep daily records of your sleep times and other events (such as caffeine or medicine use) that occur that day.

  • Caffeine, nicotine, alcohol, and drugs are not allowed throughout the study.

  • You will be asked to provide a urine sample at the beginning of the study for a drug/nicotine screen. You may also be randomly drug tested throughout the duration of the study. If the results are positive, you will not be able to continue in the study. We will not share the results with anyone outside of our research staff.

  • You may be asked to complete a test for COVID-19. This will require a small swab be inserted into both of your nostrils. If the results are positive, you will not be able to continue in the study.

  • You will be asked to follow the recommended COVID-19 mitigation strategies to reduce the risk of transmitting COVID-19 while you are in our laboratory even if you are vaccinated for COVID-19. These strategies include:

    • You will be required to complete a COVID-19 symptom screener before entering the lab. This is includes a touchless temperature check and some questions that ask you about how you are feeling, where you have traveled, whether you have been in contact with anyone who has been diagnosed with COVID-19, and whether you have been vaccinated.

    • Anytime you come to our lab, you must wear a mask that we will give to you. You will not be able to wear a cloth mask when you are in our lab.

    • If you are experiencing a fever, cough, runny nose, new rash, chills, muscle pain, sore throat, or new loss of taste or smell, then you must call our lab. You must not come to the lab.

    • If you have been in close contact with a person who has been diagnosed with COVID-19, then you must call the lab as soon as possible and you must not come to the lab.

Home Sleep Week (Study Days 1-7):

  • You will follow a rigid (strict) sleep schedule, with bedtimes and wake times similar to your usual sleep schedule. You will always have the same bedtime and same wake up time, even on the weekend. You will be required to sleep at home in the dark for 9 hours each night. You must be lying in your bed in the dark trying to sleep during the sleep times. You may not read, use a computer or electronic device, watch television, listen to music, or use a phone during this scheduled sleep time. You will not be allowed to sleep at other times outside of your scheduled sleeping hours.

  • You will be required to visit the lab at least once during the week that you sleep at home to allow us to read (download) the data from the equipment you wear into our computer and review your daily records. This is another time to ask questions about the study if you have any. This visit will take about 1 to 1.5 hours. A portion of this meeting may be completed by a video conference after you visit the lab.

  • You may receive text message reminders on your cell phone for various study related tasks while you are sleeping at home. If you don’t have a cell phone, we can lend you a cell phone with pre-loaded cards for texting. We are asking for your permission to contact you using a free text messaging service. We will show you how to stop these text message reminders if you no longer want to receive them.

Lab Week (Study Days 8-14):
During the lab session week, you will spend a total of 7 days in the lab. You will arrive in the afternoon on day 8 and you will be in the lab until the study ends on day 14. Below is a description of what will happen in the order that it will happen.

  • On day 8, you will arrive to the lab in the afternoon and participate in a “lazy boy session.” During the lazy boy session, you will be asked to stay awake in dim red light in a lazy boy recliner chair for 8 to 10 hours. You will provide a saliva sample (less than ½ teaspoon of saliva) every 30 minutes by rolling a small cylinder of dental cotton around in your mouth. You will provide about 16 to 22 saliva samples per lazy boy session. Your saliva will be tested at a later time to determine how much melatonin is in your body. This will tell us what time it is in your brain. During the lazy boy session, you can watch T.V. and movies. You can also play games or do other quiet activities with other study subjects and a member of our research staff. After the lazy boy session, you will sleep over in the lab in your own bedroom. We will tell you when you need to go to bed and wake up in the morning. You will get about 7 hours to sleep after the lazy boy session.

  • The next day (day 9), you will sleep on the same rigid (strict) sleep schedule that you had during the home sleep week (described above).

  • For the next 3 days (days 10-12), you will go to bed and wake up 1 to 3 hours earlier than usual for 3 nights. We will tell you when you need to go to bed and wake up in the morning. You will have 9 h to sleep each night.

  • During the lab session, you may also be required to sit in front of light boxes with fluorescent bulbs for no more than 3 hours on 3 days. The lights will produce bright light that is brighter than most indoor light, but not as bright as being outside on a cloudy day. Whether or not you sit in front of the light boxes will be determined random (like flipping a coin).

  • At the end of the lab session, you will participate in another lazy boy session (described above). After the lazy boy session is over, you will sleep in our lab. You will go home shortly after you wake up on day 14.

  • Food and beverages will be provided when you are in our lab, but some foods that could interfere with the study (such as caffeine, bananas, and chocolate) will not be allowed.

  • You will be breathalyzed for alcohol at the start of the lab session.

  • A person from our lab will always be in the lab when you are, even while you are sleeping. They will tell you what you need to do, prepare you food, and so forth.

  • You will be required to wear a mask while you are in the lab except when you are providing a saliva sample, eating or drinking, and sleeping. We will provide you with a new mask each day. Staff will also be wearing a mask throughout the entire lab session.

Application Process:
We have an extensive application process. If, after reading the information, you decide that you want to participate in the study, then please complete all of the questions in the questionnaire. Once we receive your completed questionnaire, we will review it and let you know if you are eligible for the next step in the process of applying for the study.

We may call you to collect some additional information. After this follow-up phone call, we may then ask you to come to the lab for a meeting. During this meeting, we will explain the study in more detail, show you the lab and equipment, and have you fill out some additional questionnaires. Only after that appointment will we be able to tell you if you are eligible to participate in the study. If you are not eligible for the study, we will not be able to tell you why.

If you are still interested, please complete, and submit the following questionnaire. If you have any additional questions, please email us at: or call us at 312-563-4781. If you return the filled-out questionnaire, you should hear from us within the next few days.

By checking the “Accept” box below and entering your name, you accept our terms and agree to provide information in the following questionnaire to determine your eligibility to participate in the Light Timing Study. If you do not agree with our terms, or you change your mind while filling out the survey, please exit your browser window to quit the questionnaire. Thank you.

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