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Item Effect of beetroot pomace consumption on acute blood pressure and postprandial blood glucose responses on healthy adults : a thesis presented in the partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics, Massey University, Albany, New Zealand(Massey University, 2023) Gorbani, ElnazBackground: Nitrate-rich beetroot juice (BRJ) supplementation has been shown to improve blood pressure (BP) levels in younger and older adults via increased nitric oxide (NO) production leading to dilation of blood vessels. Similarly, to some extent a reduction of blood glucose (BG) levels through several different mechanisms. However, limited research exists on the by-product of beetroot juice production, beetroot pomace (BRPOM), and its role in controlling BP and BG levels. Objective: To investigate and compare the changes in BP and BG levels in a 3 h period following the ingestion of BRPOM, BRJ and placebo as part of an oral glucose tolerance test (OGTT). Methods: Following an overnight fast, twelve healthy adults consumed either BRPOM (600 mg nitrate, 10 g fibre, 75 g carbohydrate), BRJ (600 mg nitrate, <1 g fibre, 75 g carbohydrate), or placebo (0 mg nitrate, <1 g fibre, 75 g carbohydrate) 15 minutes prior to the OGTT, separated by 1-week washout periods, in a single-blind, crossover design, pilot study. Blood pressure and BG levels were measured at baseline, then every 15 minutes for BG and every hour for BP during a 3 h OGTT. Results: No significant changes in SBP for BRJ (-2.3 ± 5.56 mmHg, p = 0.174), BRPOM (-3 ± 13.4 mmHg, p = 0.456), or PLA (5.2 ± 11.3 mmHg, p = 0.142) treatment group after 3 h. However, there was a trend towards significance in the differences between the three groups (p = 0.075, η²ₚ = 0.404). Clinically meaningful reductions in SBP were observed for BRJ (-2.3 ± 5.56 mmHg) and BRPOM (-3 ± 13.4 mmHg). There were no differences (p = 0.739, η²ₚ = 0.059) in mean glucose incremental area under the curve (iAUC) between BRJ, BRPOM and PLA (232.8 ± 61.9, 242 ± 54.7 and 252.4 ± 60.6 mmol/L/min, respectively). There were no differences between BRJ, BRPOM and PLA in time to peak (p = 0.269, η²ₚ = 0.313), peak glucose levels (p = 0.241, η²ₚ = 0.247), 2 h glucose levels (p = 0.565, η²ₚ = 0.150), 3 h glucose levels (p = 0.395, η²ₚ = 0.233) and percentage increment of postprandial BG (p = 0.783, η²ₚ = 0.048). Conclusion: This pilot study with a small sample size showed a large effect size and clinically meaningful attenuations for acute SBP changes following the consumption of beetroot pomace. Further investigations would be needed to explore the applicability of these findings to hypertensive individuals. However, its impact on acute BG levels remains non-significant, possibly influenced by the small sample size and participants’ baseline normoglycaemic levels. Further research is needed to explore potential effects in a hyperglycaemic population.Item The Acute Cardiorespiratory and Cerebrovascular Response to Resistance Exercise(BioMed Central Ltd, 2021-12) Perry BG; Lucas SJEResistance exercise (RE) is a popular modality for the general population and athletes alike, due to the numerous benefits of regular participation. The acute response to dynamic RE is characterised by temporary and bidirectional physiological extremes, not typically seen in continuous aerobic exercise (e.g. cycling) and headlined by phasic perturbations in blood pressure that challenge cerebral blood flow (CBF) regulation. Cerebral autoregulation has been heavily scrutinised over the last decade with new data challenging the effectiveness of this intrinsic flow regulating mechanism, particularly to abrupt changes in blood pressure over the course of seconds (i.e. dynamic cerebral autoregulation), like those observed during RE. Acutely, RE can challenge CBF regulation, resulting in adverse responses (e.g. syncope). Compared with aerobic exercise, RE is relatively understudied, particularly high-intensity dynamic RE with a concurrent Valsalva manoeuvre (VM). However, the VM alone challenges CBF regulation and generates additional complexity when trying to dissociate the mechanisms underpinning the circulatory response to RE. Given the disparate circulatory response between aerobic and RE, primarily the blood pressure profiles, regulation of CBF is ostensibly different. In this review, we summarise current literature and highlight the acute physiological responses to RE, with a focus on the cerebral circulation.Item Follow-up study of the dietary intake, anthropometric measurements, and blood pressure in children born to women in the Manawatu pregnancy study : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutritional Science at Massey University(Massey University, 2001) Al-Shami, EntesarWhen the proposal of the pilot study presented in this thesis was finally formulated, one of the first and important requirements was to obtain approval from accredited ethics committees. This proved to be a long and demanding process, but at the same time an interesting and useful experience. It was also somehow different from what was previously experienced in Kuwait, the researcher's home country. That was how the idea of presenting this thesis in two parts came into being. In the first part, the development of ethics codes and ethics committees was reviewed, a comparison of the process to obtain an ethical approval in New Zealand and in Kuwait was made, and the proposals presented to Massey University Human Ethics Committee (MUHEC) and to Manawatu-Whanganui Committee (MWEC) were outlined. Bioethics is a young discipline; the term "medical ethics" was first used at the beginning of the 19th century. However, codes of ethics of human research were only introduced towards the end of the first half of the 20th century. Hectic debates over these codes took place during the second half of the 20th century. On one side, there were growing concerns for the rights and safety of research participants, physically, psychologically and culturally, and on the other there were fears that scientific merits and benefits might be eroded by the limitations that research bioethics may enforce. These debates have resulted in amendments and changes in ethics codes, changes that probably will continue to develop during the 21st century. [From Introduction]Item Relationships between exercise, anger, hostility and resting blood pressure in women : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Psychology at Massey University(Massey University, 1998) Madigan, Gina ThereseThe present study investigated relationships between exercise, emotions of anger and hostility, and resting blood pressure. The investigation was based on a notion of 'physicality' which suggests exercise may be a source of physical and emotional empowerment for women. Recent studies reveal significant associations between exercise, components of anger, and blood pressure. The aim of the present study was to examine the possible relationship between exercise and emotions, and the possible roles of exercise as a mediating, confounding, and moderating variable in relationships between anger, hostility and resting blood pressure. One hundred and four female university students completed a questionnaire which included a measure of exercise, the Spielberger Trait Anger Scale and Anger Expression Scale, and the Cook-Medley Hostility Scale. Frequency of informal exercise was positively related to trait anger and anger temperament. Multiple regressions showed that exercise was not a mediating or confounding variable in relationships between anger, hostility and blood pressure. It did appear however, to moderate the relationship between anger expression and diastolic blood pressure. The effects of anger expression on blood pressure were also moderated by anger frequency and hostility. Blood pressure was not related to anger suppression or trait anger. It appeared that women who were more hostile were more likely to suppress their anger, as well as perceive situations as anger-provoking. Women who experienced anger frequently were more likely to use both modes of anger expression, while those women who perceived situations as anger provoking were more likely to suppress their anger only. The theoretical and methodological implications of the findings are discussed.Item The effects of rapid and prolonged changes in blood pressure on cerebral blood flow in healthy humans : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy, Massey University, Manawatu, New Zealand(Massey University, 2014) Perry, Blake GThe regulation of blood flow to the brain is complex and incompletely understood. Many local and systemic factors modulate cerebral perfusion, one of which is arterial blood pressure. The brain possesses intrinsic mechanisms which act to protect against rapid and also prolonged changes in perfusion pressure. However, recent evidence indicates that this supposedly powerful regulatory mechanism/s may not be as efficient as traditionally believed and that changes in arterial blood pressure have a profound effect on cerebral blood flow (CBF). This thesis explored different non-pharmacological means of perturbing mean arterial blood pressure (MAP) both rapidly (dynamic) and for prolonged steady-state periods (~5 min; static). Dynamic changes in blood pressure were induced via upright resistance exercise (Chapter Five) and standing Valsalva manoeuvres (VM; Chapter Six), while static changes were induced via lower body positive pressure (Chapters Seven and Eight). The effects of these changes in MAP on cerebral blood flow were assessed via transcranial Doppler ultrasound of the blood velocity in middle cerebral artery (MCAv). The findings of Chapter Five illustrated that during resistance exercise the peak mean MCAv (MCAvmean) was unchanged between loads despite the increasing MAP with the increasing relative load. Following resistance exercise, however, the hypotension observed was matched by concomitant reductions in MCAvmean, the magnitude of which was load dependent. Chapter Six investigated the role of the Valsalva manoeuvre (VM) alone in the stability of the MCAv response whilst standing. Chapter Six highlights that the VM protects the cerebral vessels during acute hypertension. In addition, more intense straining during a VM produced a similar response following the release of the manoeuvre to that seen following the resistance exercise. Thus, more pronounced decreases in blood pressure, whilst upright, do result in concomitant decreases in MCAvmean. The steady-state elevations in MAP examined in Chapters Seven and Eight increased MCAvmean with and without hypercapnia. Thus, illustrating that even when the regulatory mechanisms were functionally intact (normocapnia) the brain demonstrated a pressure passive relationship during relatively small increases in MAP. Overall, both abrupt and steady-state changes in perfusion pressure were coupled with alterations in MCAvmean. This thesis contributes to the notion that the cerebral circulation is not independent of changes in MAP, and that sustained hypercapnia impairs the autoregulatory capacity of the cerebral circulation. Importantly, this thesis shows these effects without the use of pharmacological agents to confound the interpretation of the data.Item Acute effects of whey protein, alone and mixed with other macronutrients, on blood pressure and heart rate in older men(BioMed Central Ltd, 2022-12) Oberoi A; Giezenaar C; Lange K; Jones KL; Horowitz M; Chapman I; Soenen SBACKGROUND: Caloric supplements are increasingly used by older people, aiming to increase their daily protein intake. These high caloric drinks, rich in glucose and whey-protein in particular, may result in potential harmful decreases in blood pressure (BP). The effect of ingesting whey-protein with glucose and fat on BP is unknown. It has also been assumed that the maximum fall in systolic blood pressure occurs within 2 h of a meal. METHODS: This study aimed to determine in older men, the effects of whey-protein, alone and mixed with other macronutrients, on systolic (SBP) and diastolic (DBP) blood pressure and heart rate (HR) in older men for 3 h. Thirteen older men (age 75 ± 2yrs; body mass index (BMI) 25.6 ± 0.6 kg/m2) ingested a drink on separate study days: (i) 70 g whey-protein (P280); (ii) 14 g whey-protein, 28 g carbohydrate, 12.4 g fat (M280); (iii) 70 g whey-protein, 28 g carbohydrate, 12.4 g fat (M504); or (iv) a non-caloric control drink (C). RESULTS: SBP decreased after all three nutrient drinks compared to the C, with the greatest reduction after the M504 drink (P = 0.008). Maximal decreases in SBP (C: -14 ± 2 mmHg, P280: -22 ± 2 mmHg, M280: -22 ± 4 mmHg, M504: -24 ± 3 mmHg) occurred about 2 h after drink ingestion and this fall was sustained thereafter (120-180 min: P280 and M504 vs. C P < 0.05). Maximum DBP decreases and HR increases occurred after M504, with no differences between the effects of the P280 and M280 drinks. CONCLUSIONS: The effects of whey-protein containing drinks to lower BP and increase HR appear to be primarily dependent on their energy content rather than macronutrient composition and may persist for at least 3 h after ingestion,. Pure whey-protein drinks may represent the best approach to maximize protein intake without increasing the potential for deleterious BP falls in older people. TRIAL REGISTRATION: ACTRN12614000846628 , 14/03/2019.