Student Perspectives in Cognitive Neuroscience

Does stress and disturbance in sleep duration affect quality of sleep?

Numerous research studies have been done on quality of sleep and factors that influence this. Quality of sleep has an influence on general health and quality of life, to function or perform optimally the body and brain needs rest. Does levels of stress and the duration of sleep affect the quality of sleep? Objective: This article will focus on the effect of levels of stress and duration of sleep on the quality of sleep. Method: Ten participants, male and female from different age groups where selected to participate in this research study. Results: Increase levels in stress leads to decrease in rating on quality of sleep. Disturbances or awakenings during sleep and the time it takes to fall asleep again decrease rating on quality of sleep. Conclusion: Levels of stress and the duration of sleep affect the quality of sleep.

Keywords: quality of sleep, stress, duration, disturbance

Introduction

In this study I want to investigate if levels of stress and the duration of sleeps affect an individual’s perceived quality of sleep. Is there a positive relationship between the quality and the duration of sleep? Does disturbance in sleep patterns or duration of sleep affect the quality of sleep negatively? Can levels of stress contribute negatively towards the quality of sleep? Quality of sleeps affects a person’s health and overall quality of life. Sleep is crucial to restore energy and helps us to retain information and perform better on memory tasks. During sleep restoration and rejuvenation of the body and mind takes place. What is quality of sleep? According to the National Sleep Foundation (NSF) a panel of experts established indicators of good sleep quality. They include: sleeping more while in bed, falling asleep within half an hour, waking once a night only; time awake after initially falling asleep should be 20 minutes. According to (Hyeryeon YI, Kyungrim and Chol, 2006) various questionnaires has been used to assess quality of sleep but few had all-inclusive scales making it difficult to assess the quality of sleep on various levels. They developed the Sleep Quality Scale (SQS). They identified the following domains of sleep quality: sleep initiation, sleep maintenance, depth of sleep, dreams, getting up after sleep, condition after sleep, effect on daily life, sleep amount and satisfaction with sleep. This scale can be used to assess quality of sleep and help to develop interventions for individuals with sleeping problems, but more research should be done on the discrimating abilities of the scale on the levels of quality of sleep.

A self-report dairy or journal that reports elements related to quality of sleep is essential to obtain information that can be used to get clarity on whether stress and duration of sleeps plays a role in the quality of sleep. In this study the focus will be on the level of stress experienced before going to sleep, duration of sleep and quality of sleep.

Method

Sample

Ten participants (male and female) from different age groups in Gauteng were selected and consented to participate in this study. None of them have any sleeping disorders or neurological problems. The participants are all 19 years and older and are all employed. Some of the female participants do have children. Their occupations currently range from administration to manager level.

Procedure / Measurement

Measure

A self-report sleep diary is used to explore sleep behaviour. The self-report sleep diary was kept for 7 days. The average score for each participant for the duration of the 7 days was used to analyse. This measurement is not a standardised psychological scale and thus reliability and validity of the measurement is questionable.

Reliability refers to the consistency of a measure. A measurement is said to be reliable if it can produce equivalent results if used again in similar circumstances. The reliability of the self-report sleep diary might not be consistent over time due to changes in the individual’s current situation with reference to working environment, health, levels of stress, mood and other physical factors.

Validity refers to whether measure measures or examines what it claims to measure or examine. Self-report measures might lack validity because of respondent bias or the participant’s feelings at the given moment.

Hyeryeon et al. (2006) made a valued point in stating that sleep is a private experience and is influenced by a lot of factors like, health, food, age, sex etc. and that quality of sleep is perceived differently by individuals. Self-reports can be influenced by the individual’s perception or feelings at that specific moment making it difficult to verify that the information or material is indeed reliable and valid.

Ethics

Written consent forms were obtained from each participant. The reason for the research was explained to them and confirmation was given that no confidential information would be given to any third party. All participants were informed that they could at any time withdraw their participation. Clear instructions were given to them verbally and in writing to ensure that they know exactly what is expected of them and to ensure that they executed the task correctly and as precise as possible.

The average rating for level of stress for each participant during a 7-day week was recorded and based on this average the finding was that 70% of the participants scored a 3 (quite stressful, more than usual) on the scale which indicate that they had quite stress full days with 30% confirming that their days were not that stressful with a rating of 2 (some stress but not too much). The highest ratings occurred during the week and where given by participant F and G respectively. Lower ratings were given during the weekends by all participants except A, I and D. It seems that these participants experience stressful events / days more frequently than the other participants.

Sleep Diary

Questions

• i. Time I went to bed
• ii. Time I woke up
• iii. No of hours slept last night
• iv. Number of awakenings
• v. Total time awake
• vi. How long it took to fall asleep last night (0 – 4 scale)
• vii. Real hours slept after deducting total time awake with the number of awakenings
• vii. Quality of sleep (0 – 4 scale)

Averages for all participants during the 7-day self-report diary keeping was used for questions i – vii.

Participant Stress Average for week Time to sleep average Time to wake average Hours slept before disturbance Number of awakenings Total time awake Scale of falling to sleep Real sleeping hours Quality of sleep

Results on stress and quality of sleep

The results showed that 71% of the participants (D, E, F, G, J) that rated level of stress experienced during the day 3 (quite stressful, more than usual) also rated their quality of sleep 3 (somewhat bad) or more.

The rating for quality of sleep is rated as follows:

• 0 (very good)
• 1 (fairly good)
• 2 (about average not particularly good or bad)
• 3 (somewhat bad)
• 4 (very bad)

High ratings on level of stress experienced correlates with negative quality of sleep ratings.

The graph below shows that increase level of stress experience leads to decrease rating in good quality of sleep.

There are however some of the participants (H, I) that did indicate moderate levels of stress 2 (some stress not too much) with no significant decrease in quality of sleep. Factors like duration of sleep without disturbance and total time awake as well as the amount of time these participants take to fall asleep might play a crucial role here. Other factors not sleep related might also be relevant. Participants overall mood should be consider seeing as some individuals tend to be more positive in general about things than others and might not necessarily feel that the quality of sleep they got was that bad although they might not have gotten enough sleep.

Stress

According to Medicine Net (https://www.medicinenet.com/script/main/art.asp?articlekey=20104) stress is an emotional, physical or mental reaction to tension caused by environmental or internal factors. Stress is a highly individualized experience meaning that one person might experience an event as stressful and react in accordance while another individual might not experience the same event as stressful at all. Stress can be the causative factor of many medical conditions which include poor healing, high blood pressure, diabetes to name a few. The relationship between stress and sleep is clearly indicated here as seeing that sleeping helps to repair and rejuvenate the body and lack of sleep due to stress can affect the individual tremendously on a physical level. Sleep disturbances or changes in sleeping habits are also common physical symptoms of stress.

The National Sleep Foundation (https://sleepfoundation.org/insomnia/content/what-is-insomnia) defines insomnia as an inability to fall asleep or stay asleep even in the event of the opportunity to do so. Stress causes hyperarousal which affects the balance between wakefulness and sleep which in turn can lead to insomnia. Stress increase the level of difficulty falling asleep and if an individual finds it difficult to sleep and stay asleep they might begin to experience their quality of sleep as negative.

From the study done it is clear that some of the participants do feel that their quality of sleep is not good, and they do have rather elevated levels of stress. If we consider the duration of sleep and number of awakenings together with the time it takes to fall asleep again we can conclude that there is a relationship between stress and quality of sleep. Stress affects quality of sleep negatively.

Results of duration of sleep and quality of sleep

In our table we used everyone’s average score or rating for a 7-day period reported in the self-report diary. For the analysis of the duration of sleep the following entries are of importance

1. Time participant went to bed
2. Time participant wakes up
3. Real hours slept
4. Number of awakening
5. Total time awake
6. Scale on falling asleep again
7. Quality of sleep

The research shows that 70% of the participants (B, C, E, F, H, I, J) had more than 7 hours real sleep (the total time of awake was multiplied with the number of awakenings and deducted from the hours slept before disturbance). Although they had 7 or more hours of sleep 71% (E, F, H, I, J) of them still indicated that their quality of sleep was not good and rated it 3(somewhat bad) or more according to the scale given.

The scale for quality of sleep

• 0 (very good)
• 1 (fairly good)
• 2 (about average not particularly good or bad)
• 3 (somewhat bad)
• 4 (very bad)

The participants that rated quality of sleep 3 (somewhat bad) or 4 (very bad) and slept more than 7 hours are E, F, H, I and J they also rated their stress levels 3 (quite stressful, more than usual) or more. Looking at the number of awakenings only participant J woke more than three times average while the others woke once or twice. The total time awake plays a role in their rating on the quality of sleep based on the total amount of time that these participants were awake before falling asleep again. They were awake between 15 – 40 minutes per awakening. Looking at the scale on falling asleep (0 – 4)

Scale on falling asleep

• 0 (immediately)
• 1 (after less than 5 minutes)
• 2 (after about 20 minutes)
• 3 (longer than 20 minutes but less than an hour)
• 4 (more than an hour)

All of them took 20 minutes or more to fall asleep again after each awakening. As mention in the introduction the National Sleep Foundation’s (NSF) key indicators of good sleep quality states that good quality of sleep should entail sleeping more time while in bed, falling asleep in 30 minutes or less, waking up no more than once per night; and being awake for 20 minutes or less after initially falling asleep. The participants that woke more than once and was awake for 20 minutes or more after initially falling asleep might experience their quality of sleep as not good. Although these participants fell asleep after about 20 minutes the number of awakenings influenced their perception on the quality of their sleep.

Participants A rated average stress level at 2 (some stress but not too much) and quality of sleep at 1 (fairly good) meaning that on average the participant felt that he slept quite good irrelevant of the number of hours the person slept. Participant A also indicated that he woke on average only once and stayed awake for 10 minutes in that time, he also found it quite easy to fall asleep again. Based on the information it might be concluded that Participant A finds it easier to fall asleep due to lower levels of stress experienced and less number of times awake during the 7-day period. The time it takes to fall asleep again is also rated low at 2 indicating that this participant falls asleep within 5 minutes again.

Participants D and G both rated level of stress at 3 (quite stressful, more than usual) and quality of sleep 3 (somewhat bad). Looking closer both these participants had woken up more than once and was awake for more than 30 minutes per awakening. Time to fall asleep again rating was 3 (longer than 20 minutes but less than an hour). These ratings are indicators of quality of sleep not being good due to possibly the levels of stress and with that stress difficulty falling asleep and waking more than once during the 90-minute sleep cycle. Both participants also had less than 7 hours real sleep time.

Participants B and C showed lower levels of stress rated 2 (some stress not too much), had more than 7 hours real sleep time and recorded rating on quality of sleep at 2 (about average). Although they did wake on average once or twice they were not awake for more than 20 minutes in total and only participant B had difficulty falling asleep again with a rating of 3 (more than 20 minutes but less than an hour).

Graph below indicated that disturbances in sleep / awakenings leads to decrease in quality of sleep.

Sleep

The National Sleep Foundation recommends that adults sleep between 7 to 9 hours. There are however studies that found sleeping for 6.5 hours is sufficient. The factor here is quality of sleep and not the quantity. A good night’s rest is beneficial on various levels, quality sleep can improve learning abilities, help you to gain insight into complex problems, improves memory. Physical benefits include skin health, rejuvenation of body, promotes healthy cell division etc. An individual can sleep for more than 7 hours and still feel fatigued after waking up, awakenings during the night and the time the person takes to sleep again are influential factors here, stress also plays a significant role here. Other factors could include having to tend to small children or infants during the night. Apart from stress many other factors can play a role in how the person perceive quality of sleep the morning after. This discussion focus on stress and duration of sleep.

Conclusion

From the data collected it is evident that stress and disturbances during sleep / awakenings does decrease individual’s perceived quality of sleep. Participants that had elevated levels of stress indicated that their quality of sleep was lower / decreased more than participants that had moderate levels of sleep.