Matching Items (4)
Filtering by
- Genre: Doctoral Dissertation
Description
Heart failure is a major worldwide health concern and is the leading cause of hospitalization among elderly Americans. Approximately 50% of those diagnosed with heart failure have heart failure with preserved ejection fraction (HFPEF). HFPEF presents a therapeutic dilemma because pharmacological strategies that are effective for the treatment of heart failure and reduced ejection fraction have failed to show benefit in HFPEF. Long term moderate intensity exercise programs have been shown to improve diastolic function in patients HFPEF. High intensity interval training (HIIT) has been shown to improve diastolic function in patients with heart failure and reduced ejection fraction. However, the effects of high intensity interval training in patients with HFPEF are unknown. Fourteen patients with HFPEF were randomized to either: (1) a novel program of high-intensity aerobic interval training (n = 8), or (2) a commonly prescribed program of moderate-intensity (MOD) aerobic exercise training (n = 6). Before and after four weeks of exercise training, patients underwent a treadmill graded exercise test for the determination of peak oxygen uptake (VO2peak), a brachial artery reactivity test for assessment of endothelium-dependent flow-mediated dilation (BAFMD), aortic pulse wave velocity assessment as an index of vascular stiffness and two-dimensional echocardiography for assessment of left ventricular diastolic and systolic function. I hypothesized that (1) high-intensity aerobic interval training would result in superior improvements in FMD, aortic pulse wave velocity, VO2peak, diastolic function and, (2) changes in these parameters would be correlated with changes in VO2peak. The principal findings of the study were that a one month long high intensity interval training program resulted in significant improvements in diastolic function as measured by two-dimensional echocardiography [pre diastolic dysfunction (DD) grade - 2.13 + 0.4 vs. post DD grade - 1.25 + 0.7, p = 0.03]. The left atrial volume index was reduced in the HIIT group compared to MOD ( - 4.4 + 6.2 ml/m2 vs. 5.8 + 10.7 ml/m2, p = 0.02). Early mitral flow (E) improved in the HIIT group (pre - 0.93 + 0.2 m/s vs. post - 0.78 + 0.3 m/s, p = 0.03). A significant inverse correlation was observed between change in BAFMD and change in diastolic dysfunction grade (r = - 0.585, p = 0.028) when all the data were pooled. HIIT appears to be a time-efficient and safe strategy for improving diastolic function in patients with heart failure and preserved ejection fraction. These data may have implications for cardiovascular risk reduction in this population.
ContributorsAngadi, Siddhartha (Author) / Gaesser, Glenn A (Thesis advisor) / Mookadam, Farouk (Committee member) / Swan, Pamela (Committee member) / Vega-Lopez, Sonia (Committee member) / Lee, Chong (Committee member) / Arizona State University (Publisher)
Created2012
Description
PURPOSE: Lean hypertension (HTN) is characterized by a mechanistically different HTN when compared to obese HTN. The purpose of this study is to assess whether body phenotype influences blood pressure (BP) responses following both acute and chronic exercise. METHODS: Obese (body mass index (BMI) > 30 kg/m2) and lean (BMI < 25 kg/m2) men with pre-hypertension (PHTN) (systolic BP (SBP) 120 - 139 or diastolic BP (DBP) 80 - 89 mm Hg) were asked to participate in a two-phase trial. Phase 1 assessed differences in post-exercise hypotension between groups in response to an acute exercise bout. Phase 2 consisted of a two-week aerobic exercise intervention at 65-70% of heart rate (HR) max on a cycle ergometer. Primary outcome measures were: brachial BP, central (aortic) BP, cardiac output (CO), and systemic vascular resistance (SVR) measured acutely after one exercise session and following two weeks of training. RESULTS: There were no differences between groups for baseline resting brachial BP, central BP, age, or VO2 peak (all P > 0.05). At rest, obese PHTN had greater CO compared to lean PHTN (6.3 ± 1 vs 4.7 ± 1 L/min-1, P = 0.005) and decreased SVR compared to lean PHTN (1218 ± 263 vs 1606 ± 444 Dyn.s/cm5, P = 0.003). Average 60-minute post-exercise brachial and central SBP reduced by 3 mm Hg in Lean PHTN in response to acute exercise (P < 0.005), while significantly increasing 4 mm Hg for brachial and 3 mm Hg for central SBP (P < 0.05). SVR had a significantly greater reduction following acute exercise in lean PHTN (-223 Dyn·s/cm5) compared to obese PHTN (-75 Dyn·s/cm5, P < 0.001). In lean subjects chronic training reduced brachial BP by 4 mm Hg and central BP by 3 mm Hg but training had no effect on the BP’s in obese subjects. Resting BP reduction in response to training was accompanied by reductions in SVR within lean (-169 Dyn·s/cm5, P < 0.001), while obese experienced increased SVR following training (47 Dyn·s/cm5, P < 0.001). CONCLUSION: Hemodynamic response to both acute and chronic exercise training differ between obese and lean individuals.
ContributorsZeigler, Zachary (Author) / Swan, Pamela (Thesis advisor) / Gaesser, Glenn (Committee member) / Buman, Matthew (Committee member) / Angadi, Siddhartha (Committee member) / Farouk, Mookadam (Committee member) / Arizona State University (Publisher)
Created2016
Description
Physical activity is critical for optimal health and has emerged as a viable option to improve sleep. Moderate- and vigorous-intensity physical activity comparisons to improve sleep in non-exercising adults with sleep problems is limited. The purpose was to determine the effects of moderate- or vigorous-intensity exercise on sleep outcomes and peripheral skin temperature compared to a no-exercise control. The exercise intensity preference also was determined.
Eleven women (46.9±7.0 years) not participating in regular exercise and self-reporting insomnia completed a graded maximal exercise test followed by a crossover trial of three randomly assigned conditions separated by a 1-week washout. Participants performed moderate-intensity [MIC, 30 minutes, 65-70% maximum heart rate (HRmax)] or high-intensity (HIT, 20 minutes, 1-minute bouts at 90-95% HRmax alternating with 1-minute active recovery) treadmill walking or a no-exercise control (NEC) on two consecutive weekdays 4-6 hours prior to typical bed time. A dual-function wrist-worn accelerometer/temperature monitor recorded movement and skin temperature from which sleep-onset latency (SOL), sleep maintenance, sleep efficiency, total sleep time (TST), and peripheral skin temperature changes were calculated. Participants self-reported sleep outcomes weekly, enjoyment of exercise the morning after HIT and MIC, and exercise intensity preference upon completing all conditions. Mixed models analysis of variance examined differences between and within conditions controlling for demographic characteristics and habitual physical activity.
HIT resulted in up to a 90-minute TST increase on night four (448 minutes, 95% CI 422.4-474.2) compared to nights one-three. MIC nights three (43.5 minutes, 95% CI 30.4-56.6) and four (42.1 minutes 95% CI 29.0-55.2) showed nearly a 30-minute SOL worsening compared to nights one-two. No other actigraphy-measured sleep parameters differenced within or between conditions. Self-reported sleep outcomes, peripheral skin temperature change, and exercise enjoyment between conditions were similar (p>0.05). More participants preferred lower (n=3) to higher (n=1) intensity activities.
Early evening high-intensity and moderate-intensity exercise had no effect on sleep outcomes compared to a control in non-exercising adults reporting sleep complaints. Sleep benefits from HIT may require exercise on successive days. Participants indicated partiality for lower intensity exercise. More information on timing and mode of physical activity to improve sleep in this population is warranted.
Eleven women (46.9±7.0 years) not participating in regular exercise and self-reporting insomnia completed a graded maximal exercise test followed by a crossover trial of three randomly assigned conditions separated by a 1-week washout. Participants performed moderate-intensity [MIC, 30 minutes, 65-70% maximum heart rate (HRmax)] or high-intensity (HIT, 20 minutes, 1-minute bouts at 90-95% HRmax alternating with 1-minute active recovery) treadmill walking or a no-exercise control (NEC) on two consecutive weekdays 4-6 hours prior to typical bed time. A dual-function wrist-worn accelerometer/temperature monitor recorded movement and skin temperature from which sleep-onset latency (SOL), sleep maintenance, sleep efficiency, total sleep time (TST), and peripheral skin temperature changes were calculated. Participants self-reported sleep outcomes weekly, enjoyment of exercise the morning after HIT and MIC, and exercise intensity preference upon completing all conditions. Mixed models analysis of variance examined differences between and within conditions controlling for demographic characteristics and habitual physical activity.
HIT resulted in up to a 90-minute TST increase on night four (448 minutes, 95% CI 422.4-474.2) compared to nights one-three. MIC nights three (43.5 minutes, 95% CI 30.4-56.6) and four (42.1 minutes 95% CI 29.0-55.2) showed nearly a 30-minute SOL worsening compared to nights one-two. No other actigraphy-measured sleep parameters differenced within or between conditions. Self-reported sleep outcomes, peripheral skin temperature change, and exercise enjoyment between conditions were similar (p>0.05). More participants preferred lower (n=3) to higher (n=1) intensity activities.
Early evening high-intensity and moderate-intensity exercise had no effect on sleep outcomes compared to a control in non-exercising adults reporting sleep complaints. Sleep benefits from HIT may require exercise on successive days. Participants indicated partiality for lower intensity exercise. More information on timing and mode of physical activity to improve sleep in this population is warranted.
ContributorsKurka, Jonathan M (Author) / Ainsworth, Barbara E (Thesis advisor) / Adams, Marc A (Committee member) / Angadi, Siddhartha (Committee member) / Buman, Matthew P (Committee member) / Youngstedt, Shawn D (Committee member) / Arizona State University (Publisher)
Created2016
Description
Wearable technology has brought in a rapid shift in the areas of healthcare and lifestyle management. The recent development and usage of wearable devices like smart watches has created significant impact in areas like fitness management, exercise tracking, sleep quality assessment and early diagnosis of diseases like asthma, sleep apnea etc. This thesis is dedicated to the development of wearable systems and algorithms to fulfill unmet needs in the area of cardiorespiratory monitoring.
First, a pneumotach based flow sensing technique has been developed and integrated into a face mask for respiratory profile tracking. Algorithms have been developed to convert the pressure profile into respiratory flow rate profile. Gyroscope-based correction is used to remove motion artifacts that arise from daily activities. By using Principal Component Analysis, the follow-up work established a unique respiratory signature for each subject based on the flow profile and lung parameters computed using the wearable mask system.
Next, wristwatch devices to track transcutaneous gases like oxygen (TcO2) and carbon dioxide (TcCO2), and oximetry (SpO2) have been developed. Two chemical sensing approaches have been explored. In the first approach, miniaturized low-cost commercial sensors have been integrated into the wristwatch for transcutaneous gas sensing. In the second approach, CMOS camera-based colorimetric sensors are integrated into the wristwatch, where a part of camera frame is used for photoplethysmography while the remaining part tracks the optical signal from colorimetric sensors.
Finally, the wireless connectivity using Bluetooth Low Energy (BLE) in wearable systems has been explored and a data transmission protocol between wearables and host for reliable transfer has been developed. To improve the transmission reliability, the host is designed to use queue-based re-request routine to notify the wearable device of the missing packets that should be re-transmitted. This approach avoids the issue of host dependent packet losses and ensures that all the necessary information is received.
The works in this thesis have provided technical solutions to address challenges in wearable technologies, ranging from chemical sensing, flow sensing, data analysis, to wireless data transmission. These works have demonstrated transformation of traditional bench-top medical equipment into non-invasive, unobtrusive, ergonomic & stand-alone healthcare devices.
First, a pneumotach based flow sensing technique has been developed and integrated into a face mask for respiratory profile tracking. Algorithms have been developed to convert the pressure profile into respiratory flow rate profile. Gyroscope-based correction is used to remove motion artifacts that arise from daily activities. By using Principal Component Analysis, the follow-up work established a unique respiratory signature for each subject based on the flow profile and lung parameters computed using the wearable mask system.
Next, wristwatch devices to track transcutaneous gases like oxygen (TcO2) and carbon dioxide (TcCO2), and oximetry (SpO2) have been developed. Two chemical sensing approaches have been explored. In the first approach, miniaturized low-cost commercial sensors have been integrated into the wristwatch for transcutaneous gas sensing. In the second approach, CMOS camera-based colorimetric sensors are integrated into the wristwatch, where a part of camera frame is used for photoplethysmography while the remaining part tracks the optical signal from colorimetric sensors.
Finally, the wireless connectivity using Bluetooth Low Energy (BLE) in wearable systems has been explored and a data transmission protocol between wearables and host for reliable transfer has been developed. To improve the transmission reliability, the host is designed to use queue-based re-request routine to notify the wearable device of the missing packets that should be re-transmitted. This approach avoids the issue of host dependent packet losses and ensures that all the necessary information is received.
The works in this thesis have provided technical solutions to address challenges in wearable technologies, ranging from chemical sensing, flow sensing, data analysis, to wireless data transmission. These works have demonstrated transformation of traditional bench-top medical equipment into non-invasive, unobtrusive, ergonomic & stand-alone healthcare devices.
ContributorsTipparaju, Vishal Varun (Author) / Xian, Xiaojun (Thesis advisor) / Forzani, Erica (Thesis advisor) / Blain Christen, Jennifer (Committee member) / Angadi, Siddhartha (Committee member) / Arizona State University (Publisher)
Created2020