Full metadata record
DC FieldValueLanguage
dc.contributorSchool of Nursingen_US
dc.creatorYu, Kin-ho Daniel-
dc.publisherHong Kong Polytechnic University-
dc.rightsAll rights reserveden_US
dc.titleTo investigate the effect of increasing mental loading on the change of heart rate variabilityen_US
dcterms.abstractBackground: Heart rate variability (HRV) is a useful tool to study cardiac autonomic activity. HRV has been found to relate to various medical conditions, physical and mental stress. The measurement of HRV is a reliable and non invasive tool to monitor the condition of human body. Response to mental stress can be culture specific. A large number of studies on HRV and mental stress including arithmetic stress and speech presentation have been undertaken in the West but not in Asia. Therefore, it is worthwhile to perform such a study in Hong Kong, since the problem of stress within this community has been raised in recent years. Objectives: the objectives were 1) to measure the change of different parameters of HRV when normotensive people are placed under mental stress, 2) to measure the prediction power of parameters of HRV on mental stress, and 3) to investigate the effect of personality on the response of HRV to mental stress. Design: A one group pretest and posttest study was conducted. 24 healthy males and females who were aged between 18 and 25 were recruited to take part in this study. They underwent a mental stimulation process by doing mathematical calculation for 10 minutes and post stress resting for 15 minutes with measurement of their HRV and vital signs. Outcome measure: Descriptive analysis was carried out to summarize the subjects' profile. First, one way ANOVA was conducted to find out which demographic characteristic was affecting HRV. Second, repeated measure ANOVA was performed to find out if mental stress exerted an effect on the HRV. Finally, multiple regression was used to determine the predictability of HRV in relation to mental stress. Results: The results of the study were 1) absolute value of high frequency (HF) and total power (TP) of HRV and, 2) the square root of the mean squared differences of successive NN intervals (RMSSD) and standard deviation of NN interval (SDNN) of time domain of HRV were decreased by the mental stress, where the decrease in all the four parameters represented parasympathetic withdrawal. On the other hand, there was an statistically significant increase in very low frequency (VLF) and absolute value of low frequency (LF) of HRV by mental stress by which this increase represented sympathetic activation. Moreover, it was proved statistically that HF, TP, VLF, LF, LFnm, HFnm, RMSSD and SDNN had moderate to strong predictive power of the level of stress without the problem of multicollinearity. Conclusion: The mental stress in this study was able to stimulate parasympathetic withdrawal and sympathetic activation as measured by the HRV. HRV could be a reliable predictor for level of mental stress.en_US
dcterms.extent91 p. : ill. ; 30 cm.en_US
dcterms.educationalLevelAll Masteren_US
dcterms.LCSHHong Kong Polytechnic University -- Dissertations.en_US
dcterms.LCSHHeart beat -- Measurement.en_US
dcterms.LCSHMental fatigue -- Physiological aspects.en_US
dcterms.accessRightsrestricted accessen_US

Files in This Item:
File Description SizeFormat 
b23018835.pdfFor All Users (off-campus access for PolyU Staff & Students only)1.62 MBAdobe PDFView/Open

Copyright Undertaking

As a bona fide Library user, I declare that:

  1. I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
  2. I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
  3. I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.

By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.

Show simple item record

Please use this identifier to cite or link to this item: https://theses.lib.polyu.edu.hk/handle/200/5070