Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item The impact of acoustic stimulation and daytime napping on heart rate variability and sleep architecture(Montana State University - Bozeman, College of Education, Health & Human Development, 2023) Nicevski, Jennifer Rose; Chairperson, Graduate Committee: Dawn TarabochiaReceiving adequate overnight sleep is imperative for proper autonomic nervous system function. Recent studies utilizing acoustic stimulation (AS) have shown an improvement in sleep quality when applied during nighttime sleep, although the implications of AS on napping are not known. The purpose of the current study was to assess the impact of AS during a daytime nap on sleep and autonomic function. We hypothesized that AS (0.8 Hertz monaural beats at 30 decibels) would improve heart rate variability (HRV) during non-rapid eye movement (NREM) sleep and increase time spent in slow wave sleep in young adults. 25 young healthy adult subjects (12 men, 13 women, age: 23 + or - 1 yrs, BMI: 24 + or - 1 kg/m2) took part in the study. Participants were enrolled into a randomized, placebo-controlled crossover design where they completed two 90-minute afternoon nap opportunities with or without AS, at least one day apart. During each testing session, participants were fitted with gold-standard polysomnographic (PSG) equipment and five-lead electrocardiogram (ECG). Subjective questionnaires assessing sleepiness (Epworth Sleepiness Scale) and anxiety (Spielberger State Anxiety Inventory) were given prior to and following each nap opportunity. ECG was recorded continuously starting 5 minutes prior to lights out until awakening, allowing assessment of wake and sleep HRV. Contrary to our hypothesis, there were no significant changes in total sleep time (Control: 73 + or - 4 vs. AS: 72 + or - 4 min, P=0.850), slow wave sleep (Control: 30 + or - 4 vs. AS: 31 + or - 4 min, P=0.855), or other objective sleep measurements between conditions (All P>0.05). AS did not impact sleep HRV measures (All P>0.05). However, there was a significant main effect for time where napping resulted in a significant increase in the R-R interval (F(1,19)=25.683, P<0.001) and reduction of self-report anxiety (F(1,24)=8.229, P=0.008), but these responses were not different across conditions (time x condition, P>0.05). Napping elicited a paradoxical increase of diastolic (F(1,24)=14.483, P=0.001) and mean (F(1,24)=10.857, P=0.003) arterial pressure, but again these responses were not different across conditions (time x condition, P>0.05). In summary, the current study supports beneficial impacts of daytime napping on anxiety levels, but minimal effects of AS on sleep architecture and autonomic function.Item Testing the effectiveness of heart rate variability biofeedback as a method to improve attention control(Montana State University - Bozeman, College of Letters & Science, 2023) Hood, Audrey Victoria Blackwell; Chairperson, Graduate Committee: Keith A. HutchisonThe current dissertation sought to 1) examine the relationship between working memory capacity (WMC), attention control, and high-frequency heart rate variability (HF-HRV) and 2), to implement an HRV biofeedback training with the goal of increasing resting baseline HF-HRV, and in turn, attention control task performance. In both experiments, physiological measurements were collected during a seated, resting baseline using electrocardiograph electrodes and BioNomadix receivers which transmitted signals to a BioPac MP-150/160 System. The HRV index used in this study was calculated from the inter-beat intervals and inter-breath intervals data extracted from the electrocardiograph and respiration signals. In Experiment 1, participants first underwent a resting baseline period to assess their HRV and then completed two WMC tasks. Experiment 2 took place during two laboratory sessions with a week-long at-home training between lab Sessions 1 and 2. At Session 1, participants first underwent a resting baseline period to assess their HRV and then completed two measures of WMC. They then completed three attention control tasks pre- and post-training. For the training, those randomly assigned to the HRV biofeedback condition underwent a breathing exercise, whereas those randomly assigned to the active control condition completed wordsearch puzzles. Participants were asked to practice the breathing/wordsearch exercises at home for one week. At Session 2, participants underwent a resting baseline physiological assessment followed by the three attention control tasks again. Results demonstrated that HF-HRV is weakly correlated with WMC and attention control and that brief, 5-minute sessions of HRV biofeedback are not sufficient to increase levels resting baseline HF-HRV.Item Childhood depressive disorder symptoms: relations with two physiological indices of emotion regulation(Montana State University - Bozeman, College of Letters & Science, 2019) Armstrong, Eleanor Jane; Chairperson, Graduate Committee: Brandon ScottTheoretical models of depression postulate that one's ability to regulate emotions may be a core factor in the development of depressive disorder symptoms. The present study aimed to understand how physiological measures of emotion regulation are related to depressive disorder symptoms among a community sample of 7-10 year-old children. Specifically, we sought to investigate how resting heart rate variability and the change in heart rate variability from a resting baseline to a stressor are related to child- and-caregiver- reported depressive symptomology. The children's physiological measures (i.e., heartbeat patterns, respiration) used to calculate high-frequency heart rate variability for each task were collected as the child sat quietly (3 minutes), watched a relaxing Coral Reef video (3 minutes), traced a star pattern while looking in a mirror (3 minutes), and played Hungry, Hungry Hippos on an iPad (3 minutes). In addition, children and their primary caregivers completed a series of questionnaires about the child and family demographics and child's depressive disorder symptoms. We conducted bivariate correlations, paired samples t-tests, multiple regression analyses (controlling for age, gender, and mean respiration rate at baseline) to examine the relations between both resting heart rate variability and change in heart rate variability in response to a stressor or positive task and child- and caregiver-reported depressive disorder symptoms. We found a significant relation between the child-reported depressive disorders and the change in HRV from resting baseline (traditional and video) to the stress task. However, we did not find that gender moderated this relation, nor did we find any significant relations between the resting baseline (traditional and video) and child-or-caregiver-reported depressive symptoms. Finally, not associations were found between and the change in HRV from resting baseline (video) or the Mirror Star Tracer task Baseline to the Hungry Hungry Hippo task and child-or-caregiver-reported depressive symptoms. Future research should consider the nature of the task demands relative to arousal and also the diversity and size of the sample. Our findings demonstrated a unique pattern in HRV change from resting baseline (traditional and video) to a stress task that allow for new questions to be asked and a foundation for further research.Item Validation of the 1-mile walking test in young adults at maximal and submaximal walking intensities(Montana State University - Bozeman, College of Education, Health & Human Development, 2002) Keller, Christopher PaulItem Comparison of heart rate and oxygen uptake relationship in water with that on land(Montana State University - Bozeman, College of Education, Health & Human Development, 1988) Klapperich, Lori Ann