Battle of the Clocks

Battle of the Clocks




Higher levels of exercise have been linked to better sleep but it is unclear whether the time of day at which individuals exercise plays a role. This project examines whether the regularity and timing of exercise (early versus late), and circadian-type impact sleep. We examine these questions among athlete and non-athlete students to determine when (and for whom) does exercising lead to better sleep.

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Study Objectives:

  • To determine whether circadian-type (i.e., morningness-eveningness preference) moderates the association between physical activity and sleep
  • To examine whether stress mediates the relationship between physical activity and sleep

Key Constructs: sleep, stress, physical activity, and circadian-type

Sample: athlete and non-athlete students at Wesleyan University

Click here for a copy of the Participant Consent Form.

Check out the “Sleep N’ Spit” instructional video below:


Q: Where do I go to pick up my payments and materials?

A: All study materials and payments can be picked up at the Sleep and Psychosocial Adjustment Lab, located in Judd Hall, Room 106. Come through the main doors of Judd Hall; make a left; the S.P.A Lab is located at the end of that hallway.

Q: If I participate in the Battle of the Clocks study, how much will I be paid?

A: Participants will receive $40.00 as compensation for their participation in the study. You will receive $10.00 in cash after you complete Part 1 (online baseline survey) and $30.00 in cash after you complete Part 2 (7-day daily sleep and spit). Additionally, participants who adhere to the study’s protocol and drop off their spit samples at the required time (i.e., mid-week of the 7-day period) will be entered to win one of two Fitbits.

Q: If I am assigned to this study for Psychology 105, will I still be paid?

A: Participants who have been assigned to the Battle of the Clocks research study via the Participant Pool SONA system are NOT eligible to receive payment as compensation. Instead participants will be allotted a 4-hour credit towards their research credit requirement.

Q: What happens if I forget to complete a pick-up or drop-off?

A: You must attend your scheduled 30-minute time slot in order to complete Part 2 of the study, because we will need to get you set up with your sleep monitor and other study materials (e.g., plastic vials and labels for your saliva samples). We will send you a reminder message (either via text or email) a couple days before your scheduled in-lab time slot. If for some reason you are not able to make your scheduled time slot, we will be happy to reschedule for a different day and/or time!

In terms of drop-off: we cannot overemphasize the importance of your mid-week spit drop off. The concentrations of cortisol in saliva samples begin to decline after 4 days and so in order to have valid data, we need the spit samples to be dropped off on Thursday. If for some reason you are unable to drop off your spit on Thursday, please do your best to drop off your samples by noon on Friday.

Q: Can I take off my sleep monitor during the week of the study?

A: We ask that you wear your sleep monitor all day during the 7-day period for Part 2 of the study (except when swimming). The devices are quite costly and so, we ask that you take extreme care with the device. The device will NOT be able to track your sleep if it is not worn on your wrist.

Q: Why do you need samples of my spit?

A: One of the major variables in the Battle of the Clocks study is stress. One specific physiological system that responds to stress is the hypothalamic-pituitary-adrenal (HPA) axis system. When we experience stress at the psychological level (e.g., worries about our relationships with friends), this triggers a cascade of reactions in the body involving the hypothalamus, the pituitary gland and the adrenal cortex. One of the end products of that system in the hormone, cortisol. Cortisol can be measured through small samples of saliva. This is one system by which researchers investigate how stress “gets under the skin”. In other words, because the H.P.A axis responds the stress, we will be able to get insight into your stress response system by measuring your cortisol through your saliva. And why do we need so many saliva samples (i.e., 4x a day for 7 days) Because it’s not just about how much cortisol your body produces but how the levels of cortisol CHANGE throughout the day, especially, within the first 45 minutes of waking up (i.e., the first 3 samples of the day). The bedtime sample is just as important, to determine how cortisol levels at bedtime are associated with your sleep.

Q: What should I do if I am late to take a spit sample?

A: The timing of the spit samples is extremely crucial to the validity of the cortisol data. Cortisol levels take on a very distinct pattern across the day and we have meticulously timed your spit samples to correspond to the most critical points in the day when we can capture the changes in cortisol patterns. Thus, it is out of scientific rigor that we are asking you to be so precise with your samples. That said, the data will be useless if cannot account or explain any inconsistencies with the timing of the sample. For this reason, if you are ever late to take your sample, PLEASE PLEASE BE HONEST IN REPORTING THE ACTUAL TIME OF THE SAMPLE INSTEAD OF INDICATING AN INACCURATE TIME JUST TO PLEASE US. We promise that you will not get in any trouble! It is better to know the true time of a late sample than an inaccurate labeled sample or no sample at all.

Q: What should I do if I forget to take a spit sample?

A: If you forget to take your sample, skip it. And be sure to stick with your schedule for the next sample or the next day.

Q: Can I see my individual results from the Battle of the Clocks study?

A: Upon completion of the Battle of the Clocks study, the research team will e-mail you a “sleep summary report” from the 7 days that you wore the sleep monitor. You will be e-mailed you report by the last day in July, 2017. Your sleep summary report with provide you with information only from the sleep monitor (not your survey responses): bedtime, wake time, sleep duration, sleep onset latency, sleep efficiency, and night awakenings.

Q: What is the point of Battle of the Clocks research study?

A: The purpose of the Battle of the Clocks research study is to examine associations among sleep, stress, physical activity, and circadian-type (i.e., morningness-eveningness) in relation to other aspects of university life (e.g., relationships, substance use and academic performance) in both athlete- and non-athlete students at Wesleyan university. Click on the following link to see a promotional video for the study on our page:

Q: How do I take a spit sample?

A: Taking your spit sample is easy! Well, it certainly gets easier the more often you do it. So we promise that you’ll be a ‘spit pro’ by the end of the study!!

  1. a) Get out your vial and label for the correct day and type of sample.
  2. b) Take out your straw from the bag provided.
  3. c) Uncover your vial and place one end of the straw in the vial (but don’t let the straw touch the bottom of the vial). Place the other end of the straw in between your lips so that you expel the saliva in your mouth into the vial THROUGH the straw.
  4. d) Fill up the vial with saliva (between 1.6ml and 1.8ml) – You can do it!!
  5. e) Cover your vial (nice and tight!).
  6. f) Write the current time on your label.
  7. g) Peel off that label and stick it around the body of your vial (below the cover/cap of the vial).

Note that some people have no trouble generating spit, other people find it a bit difficult. If you are having difficulty generating saliva, think about your favourite food or a lemon. You can also do the “chewing motion” (i.e., pretend that you have food in your mouth and chew).

There are 4 types of samples:

1) ‘Wake’ sample (yellow) – to be taken AS SOON AS YOU WAKE UP, even before your feet hit the floor! We advise that you keep your plastic vial for your ‘Wake’ sample next to your nightstand so that it is the first thing you do when you wake up (even before checking your phone messages). Once you are done your wake sample, set your alarm to go off in 30 minutes for sample 2.

2) ‘Wake + 30” (red) – to be taken at exactly 30 minutes after the Wake sample. After you have taken your “Wake +30” sample, set your alarm to go off in 15 minutes for sample 3.

3) Wake + 45” (white) – to be taken 45 minutes after your “Wake” sample.

4) “Bedtime” (violet) – to be taken just before you turn in for bed.

Click on this link for an illustrated video on how take your spit samples: {insert video link}

Q: What are morning and evening diary entries?

A: One of the cool things about the design of the Battle of the Clocks study, is the day-to-day assessments of participants’ sleep and daily activities. By including multiple, repeated  assessments over 7 days, we will be able to determine how activities, thoughts and emotions during the day affect your sleep THAT NIGHT and also determine how your sleep at night affect your daily activities the NEXT DAY. We are really interested in capturing the day-to-day variability in your sleep and daily activities and one way to capture that is through daily diaries. The diaries are meant to give us a snapshot into your day. The morning diaries ask questions about you sleep from the previous night to determine how well you THINK you slept (this is important because some of the information the participants report may be different from the information that we get from the sleep monitors so both pieces of information are valuable! The Evening diaries ask questions about your daily experiences regarding physical activity, stress, and diet. It is important that you keep up with the morning and evening diaries each day because the link expires so as not to get you confused with the days in case you missed a day.

Q: Who will see the results of my study?

A: We understand and appreciate your concern about the use and distribution of your data. The baseline survey asks some very personal questions and your saliva provides us with information about your physiological functioning – an extremely personal matter. Thus, ( (Professor Tavernier) vow to guard your data with the strictest level of confidence. Your personal, individual data will NEVER be shared with anyone: coaches, professors, Wesleyan staff, parents etc. When we collect data, we are interested in patterns of responses across individuals and are not concerned with any ONE particular individual’s responses. So, when we analyze the data and present it at research talks, conferences etc, we will be presenting PATTERNS of responses (e.g., university students in our sample reported being more stress during the week than on the weekends). We will never present any information about a particular individual.

It is important to note that even if you know the student researchers in the lab, they will NEVER be able to match your name to your survey responses. In fact, we have assigned each one of you a generic 6-digit number that replaces your name in the data file. I (Professor Tavernier) will be the only one that has access to the data file with your name attached. Any student who work in the lab will be working with a de-identified file – that is, your names will be deleted and instead replaced with the 6-digit ID number.

Q: When will I find out if I won the Fitbit raffle?

A: The winners for the raffle will be announced via e-mail on Monday May 15.

Q: What should I do if I decide that I no longer want to be part of the study?

A: Like every psychological research study, participation in the Battle of the Clocks study is voluntary and you can withdraw at any time without any penalty to you. If you would like to withdraw from the study, please inform the primary researcher ( or Call (860) 685-2369) and return the sleep monitor to the Sleep and Psychosocial Adjustment lab (Judd 106).

Q: Who can I contact for support if I feel distressed during or after the Battle of the Clocks study?

A: If you experience any distress during or after participation in the Battle of the Clocks study, we encourage you to seek assistance from a trained mental health professional. Here is the contact information for counseling services at Wesleyan University (this information is also provided in the confirmation email you received after completing the online survey (Part 1) of the study.

Below are options for mental health services at Wesleyan and in the wider Middletown community should you require any mental health support:

–        Call:  860.685.2910 or 860.685.3143; Monday-Friday (8 AM – 4:30 PM); Email:

–        On-call clinician: 860.685.2910

–        Crisis appointments are available Monday – Friday in the afternoons.  To schedule a crisis appointment: 860.685.3143.

  • Middletown community:

Q: Who should I contact if I have problems completing Part 1 or Part 2 of the study?

A: If you have any questions or concerns about the study, please do not hesitate to get in touch with the research team either via E-mail: or Call: (860) 685-2369. You may also drop in to speak with Professor Tavernier (Judd Hall, Room 106-A) or a member from the research team (Judd 106).

Q: Can I wear my sleep monitor in the shower?

A: Yes, your device is waterproof up to IPX7 standards, meaning that it can be immersed in water up to 1 meter deep for up to 30 minutes without any damage.

Q: Can I go swimming with my sleep monitor?

A: Your device is waterproof up to IPX7 standards, meaning that it can be immersed in water up to 1 meter deep for up to 30 minutes without any damage. As such, we do NOT recommend that you go swimming with your sleep monitor. If you plan on going swimming at some point during the day before returning home, we advise that you leave the device home and wear it once you get back home.