Study of effects of acute sleep deprivation on inflammatory markers, oxidant status and autonomic activity and the relationship between their changes

Ankita Priya, (2019) Study of effects of acute sleep deprivation on inflammatory markers, oxidant status and autonomic activity and the relationship between their changes. Masters thesis, Christian Medical College, Vellore.


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INTRODUCTION: Sleep is a phenomenon that has existed throughout the evolutionary process. Humans spend about one-third of their lifetime or approximately eight hours per night, sleeping. Yet the purpose of sleep continues to intrigue scientists over the globe and there have been multiple theories to explain and understand the need to ‘sleep’. Several theories have suggested that sleep may be required for energy conservation, as is seen with hibernating mammals or for brain restoration and memory consolidation. Sleep affects the mental and physical health of an individual. A sufficient amount of sleep is essential for optimal health, immune function and cognition. Sleep deprivation is the loss of sleep either due to inadequate sleep time, interrupted or fragmented sleep, or a combination of both. In the modern society, lifestyle related factors, work pressures and prolonged use of electronic gadgets contribute to sleep loss. Chronic sleep deprivation increases stress hormones, insulin resistance and sympathetic activation and increases the risk for developing cardiovascular diseases and metabolic disorders such as obesity and diabetes. OBJECTIVES: 1. To study the effects of acute sleep deprivation on blood levels of Malondialdehyde (MDA) and Superoxide dismutase (SOD), the biomarkers of oxidative stress, blood levels of highly sensitive C- reactive protein (hsCRP), the inflammatory marker and Short-term Heart Rate Variability (HRV) indices, the measures of autonomic activity. 2. To study the correlation/ association between the changes in above parameters. 3. To perform a sub-group analysis of the changes in the parameters. 4. To study the efficacy of a new technique to monitor, record and document acute sleep deprivation under natural settings. METHODS: Twenty volunteers of age 20- 40 years who were doctors including staff and post graduate students of the institution were recruited to undergo 36 hours of acute sleep deprivation, if they met the inclusion criteria of having an average sleep duration of >=6 hours per night (from 2 week sleep log) and Epworth sleepiness scale (ESS) score 10 (indicator of daytime sleepiness). The Sleep deprivation protocol required the volunteer to be under surveillance of a video camera recorder when they were in their room/home, inclusive of the night hours. They were also required to maintain a record of the wake activities, every hour, throughout the 36 hours of sleep deprivation, in the Log-sheet provided. The video recording and the log-sheet was reviewed to ensure subject compliancy, further to which data collected from subject was considered for analysis. Baseline levels of serum hsCRP, serum MDA, blood SOD and HRV indices (from a 5-min lead II ECG recording) was estimated on the evening prior to the start of the Sleep deprivation protocol. The same parameters were estimated again, at end of 36 hours of sleep deprivation. All study variables were summarized using descriptive statistical methods with mean (SD) or median (IQR). Paired t test / Wilcoxon signed rank test was used to compare the Pre and post values depending on the data normality. Correlation between all study variables was assessed using Pearson’s or Spearman’s correlation coefficient. RESULTS: Sleep deprivation did not produce any significant overall changes in any of the parameters in all the twenty subjects however subgroup analysis and correlation studies revealed significant findings. The changes in hsCRP had a negative correlation with changes in total power (r= -0.4496, p=0.0467) such that higher the changes in the total power (LF+HF), lower were the changes in hsCRP levels following sleep deprivation. The implication was that doctors with higher total HRV after sleep deprivation had lower levels of inflammation. The change in the Total power showed a significant positive correlation with changes in the LF power (r= 0.603, p=0.0049) but not changes in HF power (r= -0.2872, p=0.2195). This indicates that increases in total power were mainly due to increase in LF power. Sleep deprivation produced significant lowering effect of SOD levels (Median (IQR)) from baseline in females {-0.004(-0.009; 0)} compared to males {0.003(-0.009; 0.008)} (p= 0.0478). Sleep deprivation produced a significant increasing effect in Median (IQR) MDA levels from baseline in doctors of clinical {0.23(-0.78; 0.50)} compared to non-clinical specialty {-0.14(-1.08; 0.25)} (p= 0.0494). The results of our study reveal the vulnerability of female doctors and clinical doctors to oxidative stress produced by sleep deprivation. CONCLUSION: Although we found that sleep deprivation did not produce significant changes in the various measured parameters in the overall study sample, yet the difference in the changes in the oxidative stress markers between the various sub groups have revealed important results. We have thus been able to identify doctors or groups of doctors who may be at risk from sleep deprivation in terms of buildup of oxidative stress. The female clinicians being at the greatest risk of developing oxidative stress. The findings though should be confirmed in a larger study sample. Our study has also found that those doctors who had responded with an increase in the inflammatory marker hsCRP after sleep deprivation had a reduction in their frequency-domain total HRV after sleep deprivation. This means that those who had a reduction in the hsCRP after sleep deprivation were those who had increased HRV (increased total power as revealed by frequency domain analysis) after sleep deprivation. Our study has also revealed that those who responded with increases in total power after sleep deprivation did so by an increase in the LF power rather than by an increase in the HF power. The implication is that an increased response of the sympathetic system may in fact be a protective response of the body to combat the state of stress produced by acute sleep deprivation. Further studies need to be done to analyze the association between the inflammatory response and the cardiac autonomic activity. The work culture of the modern era does not exempt anyone from sleep deprivation, as work pressures and pressures to meet deadlines are rampant across many occupations and in both clinical and non-clinical doctors. Thus, there is a need to improve the overall antioxidant mechanisms in the vulnerable groups by adequate remedial measures such as regular exercises, nutritional supplements and adopting a healthy and a routine lifestyle.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Acute sleep deprivation, MDA, SOD, hsCRP, HRV, doctors.
Subjects: MEDICAL > Physiology
Depositing User: Subramani R
Date Deposited: 23 Aug 2019 02:21
Last Modified: 23 Aug 2019 02:21

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