Journal Articles
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Item No difference in mean middle cerebral artery blood velocity responses between lower- and upper-body unilateral resistance exercise in untrained individuals(John Wiley and Sons Ltd on behalf of The Physiological Society, 2025-10-06) Korad S; Mündel T; Perry BGDynamic resistance exercise (RE) produces sinusoidal fluctuations in blood pressure that are mirrored by middle cerebral artery blood velocity (MCAv). However, whether lower- or upper-body RE elicits a differential cerebrovascular response has not yet been examined. We investigated the cerebrovascular response to lower-body RE versus upper-body RE in 15 healthy untrained individuals (12 females and 3 males; mean ± SD; age 25 ± 6 years, height 179 ± 10 cm, weight 71 ± 15 kg and body mass index 24 ± 6 kg/m2). Participants completed four sets of 10 paced repetitions (15 repetitions/min) of unilateral leg-extension exercise and unilateral bicep-curl exercise at 60% of predicted one-repetition maximum (leg extension 30 ± 9 kg and bicep curl 7 ± 3 kg). Beat-to-beat blood pressure, bilateral MCAv and partial pressure of end-tidal carbon dioxide were measured throughout. Within-exercise mean arterial blood pressure (MAP) and mean MCAv were averaged across the set. Additionally, zenith, nadir and zenith-to-nadir difference in MAP and mean MCAv for each repetition were averaged across each set. Baseline measures preceding each set were not different for all dependent variables, with no significant interaction differences observed (all p > 0.161). The mean MCAv within exercise decreased across sets (set effect p < 0.001), but MAP did not (p = 0.071). No interaction effects were observed for any dependent variables (all p > 0.06), However, there was a zenith-to-nadir difference in mean MCAv (p = 0.008), although post hoc tests revealed no significant difference between exercises (all p > 0.078). There were no differences in the cerebrovascular and cardiovascular responses to lower- and upper-body RE, with similar sinusoidal fluctuations in MAP and MCAvmean present during both exercises.Item Cardiovascular effects of intravenous vatinoxan in wild boars (Sus scrofa) anaesthetised with intramuscular medetomidine-tiletamine-zolazepam(John Wiley and Sons Ltd on behalf of British Veterinary Association, 2022-01-21) Einwaller J; Meyer LCR; Auer U; Raekallio M; Nowack J; Haw A; Vetter S; Painer J; Stalder GBackground: The potent sedative medetomidine is a commonly used adjunct for the immobilisation of non-domestic mammals. However, its use is associated with pronounced cardiovascular side effects, such as bradycardia, vasoconstriction and decreased cardiac output. We investigated the effects of the peripherally-acting alpha-2-adrenoceptor antagonist vatinoxan on cardiovascular properties in medetomidine-tiletamine-zolazepam anaesthetised wild boar (Sus scrofa). Methods: Twelve wild boars, anaesthetised twice with medetomidine (0.1 mg/kg) and tiletamine/zolazepam (2.5 mg/kg) IM in a randomised, crossover study, were administered (0.1 mg/kg) vatinoxan or an equivalent volume of saline IV (control). Cardiovascular variables, including heart rate (HR), mean arterial blood pressure (MAP), pulmonary artery pressure (PAP), pulmonary artery occlusion pressure (PAOP) and cardiac output (CO), were assessed 5 min prior to vatinoxan/saline administration until the end of anaesthesia 30 min later. Results: MAP (p < 0.0001), MPAP (p < 0.001) and MPAOP (p < 0.0001) significantly decreased from baseline after vatinoxan until the end of anaesthesia. HR increased significantly (p < 0.0001) from baseline after vatinoxan administration. However, the effect on HR subsided 3 min after vatinoxan. All variables remained constant after saline injection. There was no significant effect of vatinoxan or saline on CO. Conclusion: Vatinoxan significantly reduced systemic and pulmonary artery hypertension, induced by medetomidine in wild boar.Item Larger reductions in blood pressure during post-exercise standing, but not middle cerebral artery blood velocity, in resistance-trained versus untrained individuals.(John Wiley and Sons Ltd on behalf of The Physiological Society, 2024-12-25) Korad S; Mündel T; Perry BG; Ogoh SDynamic resistance exercise (RE) produces sinusoidal fluctuations in blood pressure, with hypotension and cerebral hypoperfusion commonly observed immediately following RE. Whether the cerebral vasculature adapts to these regular blood pressure challenges is unclear. This study examined the cerebrovascular response to post-dynamic RE orthostasis. RE-trained (n = 15, female = 4) and healthy untrained individuals (n = 15, female = 12) completed five stands: one after seated rest, with each of the subsequent four stands occurring immediately following a set of 10 repetitions of unilateral leg extension exercise at 60% of their one repetition maximum. Beat-to-beat blood pressure, mean middle cerebral artery blood velocity (MCAvmean) and end-tidal carbon dioxide were measured throughout. During standing the mean arterial blood pressure (MAP) and MCAvmean nadirs were identified. There was no difference between groups for age (mean ± SD, 26 ± 7 RE-trained vs. 25 ± 6 years untrained, P = 0.683) or weight (78 ± 15 vs. 71 ± 15 kg, P = 0.683). At MAP nadir during the post-exercise stand, a greater reduction in MAP was observed in the RE-trained group (e.g., set 4, -45 ± 11 vs. -36 ± 6 mmHg, training effect P = 0.026). However, post-exercise stand MCAvmean at MCAvmean nadir was not different (e.g., set 4, -20 ± 7 vs. -17 ± 6 cm/s, interaction effect P = 0.478). Rate of regulation was higher in the RE-trained group (set 1, 0.301 ± 0.170 vs. 0.167 ± 0.009, training effect P = 0.023). Despite RE-trained individuals demonstrating greater absolute reductions in MAP during orthostasis following RE, there were no differences in MCAvmean, suggesting that habitual RE may mitigate post-exercise cerebral hypoperfusion.Item Effectiveness of a Sodium-Reduction Smartphone App and Reduced-Sodium Salt to Lower Sodium Intake in Adults With Hypertension: Findings From the Salt Alternatives Randomized Controlled Trial.(JMIR Publications, 2023-03-09) Eyles H; Grey J; Jiang Y; Umali E; McLean R; Te Morenga L; Neal B; Rodgers A; Doughty RN; Ni Mhurchu C; Buis LR; Eysenbach GBACKGROUND: Even modest reductions in blood pressure (BP) can have an important impact on population-level morbidity and mortality from cardiovascular disease. There are 2 promising approaches: the SaltSwitch smartphone app, which enables users to scan the bar code of a packaged food using their smartphone camera and receive an immediate, interpretive traffic light nutrition label on-screen alongside a list of healthier, lower-salt options in the same food category; and reduced-sodium salts (RSSs), which are an alternative to regular table salt that are lower in sodium and higher in potassium but have a similar mouthfeel, taste, and flavor. OBJECTIVE: Our aim was to determine whether a 12-week intervention with a sodium-reduction package comprising the SaltSwitch smartphone app and an RSS could reduce urinary sodium excretion in adults with high BP. METHODS: A 2-arm parallel randomized controlled trial was conducted in New Zealand (target n=326). Following a 2-week baseline period, adults who owned a smartphone and had high BP (≥140/85 mm Hg) were randomized in a 1:1 ratio to the intervention (SaltSwitch smartphone app + RSS) or control (generic heart-healthy eating information from The Heart Foundation of New Zealand). The primary outcome was 24-hour urinary sodium excretion at 12 weeks estimated via spot urine. Secondary outcomes were urinary potassium excretion, BP, sodium content of food purchases, and intervention use and acceptability. Intervention effects were assessed blinded using intention-to-treat analyses with generalized linear regression adjusting for baseline outcome measures, age, and ethnicity. RESULTS: A total of 168 adults were randomized (n=84, 50% per group) between June 2019 and February 2020. Challenges associated with the COVID-19 pandemic and smartphone technology detrimentally affected recruitment. The adjusted mean difference between groups was 547 (95% CI -331 to 1424) mg for estimated 24-hour urinary sodium excretion, 132 (95% CI -1083 to 1347) mg for urinary potassium excretion, -0.66 (95% CI -3.48 to 2.16) mm Hg for systolic BP, and 73 (95% CI -21 to 168) mg per 100 g for the sodium content of food purchases. Most intervention participants reported using the SaltSwitch app (48/64, 75%) and RSS (60/64, 94%). SaltSwitch was used on 6 shopping occasions, and approximately 1/2 tsp per week of RSS was consumed per household during the intervention. CONCLUSIONS: In this randomized controlled trial of a salt-reduction package, we found no evidence that dietary sodium intake was reduced in adults with high BP. These negative findings may be owing to lower-than-anticipated engagement with the trial intervention package. However, implementation and COVID-19-related challenges meant that the trial was underpowered, and it is possible that a real effect may have been missed. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12619000352101; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=377044 and Universal Trial U1111-1225-4471.Item The effects of habitual resistance exercise training on cerebrovascular responses to lower body dynamic resistance exercise: A cross-sectional study.(John Wiley and Sons Ltd on behalf of The Physiological Society., 2024-06-18) Korad S; Mündel T; Perry BG; Bailey DDynamic resistance exercise (RE) produces sinusoidal fluctuations in blood pressure with simultaneous fluctuations in middle cerebral artery blood velocity (MCAv). Some evidence indicates that RE may alter cerebrovascular function. This study aimed to examine the effects of habitual RE training on the within-RE cerebrovascular responses. RE-trained (n = 15, Female = 4) and healthy untrained individuals (n = 15, Female = 12) completed four sets of 10 paced repetitions (15 repetitions per minute) of unilateral leg extension exercise at 60% of predicted 1 repetition maximum. Beat-to-beat blood pressure, MCAv and end-tidal carbon dioxide were measured throughout. Zenith, nadir and zenith-to-nadir difference in mean arterial blood pressure (MAP) and mean MCAv (MCAvmean) for each repetition were averaged across each set. Two-way ANOVA was used to analyse dependent variables (training × sets), Bonferroni corrected t-tests were used for post hoc pairwise comparisons. Group age (26 ± 7 trained vs. 25 ± 6 years untrained, P = 0.683) and weight (78 ± 15 vs. 71 ± 15 kg, P = 0.683) were not different. During exercise average MAP was greater for the RE-trained group in sets 2, 3 and 4 (e.g., set 4: 101 ± 11 vs. 92 ± 7 mmHg for RE trained and untrained, respectively, post hoc tests all P = < 0.012). Zenith MAP and zenith-to-nadir MAP difference demonstrated a training effect (P < 0.039). Average MCAvmean and MCAvmean zenith-to-nadir difference was not different between groups (interaction effect P = 0.166 and P = 0.459, respectively). Despite RE-trained individuals demonstrating greater fluctuations in MAP during RE compared to untrained, there were no differences in MCAvmean. Regular RE may lead to vascular adaptations that stabilise MCAv during RE.Item Cerebrovascular and cardiovascular responses to the Valsalva manoeuvre during hyperthermia.(John Wiley & Sons Ltd on behalf of Scandinavian Society of Clinical Physiology and Nuclear Medicine, 2023-06-18) Perry BG; Korad S; Mündel TBACKGROUND: During hyperthermia, the perturbations in mean arterial blood pressure (MAP) produced by the Valsalva manoeuvre (VM) are more severe. However, whether these more severe VM-induced changes in MAP are translated to the cerebral circulation during hyperthermia is unclear. METHODS: Healthy participants (n = 12, 1 female, mean ± SD: age 24 ± 3 years) completed a 30 mmHg (mouth pressure) VM for 15 s whilst supine during normothermia and mild hyperthermia. Hyperthermia was induced passively using a liquid conditioning garment with core temperature measured via ingested temperature sensor. Middle cerebral artery blood velocity (MCAv) and MAP were recorded continuously during and post-VM. Tieck's autoregulatory index was calculated from the VM responses, with pulsatility index, an index of pulse velocity (pulse time) and mean MCAv (MCAvmean ) also calculated. RESULTS: Passive heating significantly raised core temperature from baseline (37.9 ± 0.2 vs. 37.1 ± 0.1°C at rest, p < 0.01). MAP during phases I through III of the VM was lower during hyperthermia (interaction effect p < 0.01). Although an interaction effect was observed for MCAvmean (p = 0.02), post-hoc differences indicated only phase IIa was lower during hyperthermia (55 ± 12 vs. 49.3 ± 8 cm s- 1 for normothermia and hyperthermia, respectively, p = 0.03). Pulsatility index was increased 1-min post-VM in both conditions (0.71 ± 0.11 vs. 0.76 ± 0.11 for pre- and post-VM during normothermia, respectively, p = 0.02, and 0.86 ± 0.11 vs. 0.99 ± 0.09 for hyperthermia p < 0.01), although for pulse time only main effects of time (p < 0.01), and condition (p < 0.01) were apparent. CONCLUSION: These data indicate that the cerebrovascular response to the VM is largely unchanged by mild hyperthermia.Item Pharmacokinetics of Nitrate and Nitrite Following Beetroot Juice Drink Consumption(MDPI (Basel, Switzerland), 2021-01-20) Jakubcik EM; Rutherfurd-Markwick K; Chabert M; Wong M; Ali ABACKGROUND: Nitrate (NO3 -)-rich beetroot (BR) juice supplementation has been shown to improve cardiovascular function via reduction to nitrite (NO2 -) and then to the bioactive molecule nitric oxide (NO). However, limited research exists for the role of inorganic NO2 - that is contained naturally within BR. OBJECTIVE: As BR juice can naturally contain both NO3 - and NO2 - the objective of this study was to evaluate the individual effects of NO3 - and NO2 - consumed from BR on plasma [NO3 -]/[NO2 -] and their subsequent effects on various cardiovascular measures. DESIGN: In four separate treatments, 11 healthy adults consumed 250 mL of BR containing one of the following: (i) high NO3 -, low NO2 - (HL; 572 mg NO3 -, 32 mg NO2 -); (ii) medium NO3 -, medium NO2 - (MM; 280 mg NO3 -, 237 mg NO2 -); (iii) low NO3 -, medium NO2 - (LM; 43 mg NO3 -, 262 mg NO2 -); (iv) placebo (PL; low NO3 -, low NO2 -: 8 mg NO3 -, 5.8 mg NO2 -). Plasma [NO3 -]/[NO2 -], blood pressure, heart rate, mean arterial pressure (MAP), cardiac output and stroke volume were measured at baseline and every hour or second hour for 6 h post-BR consumption. OUTCOMES: Ingestion of the HL and MM BR increased plasma [NO2 -] and [NO3 -] after 2 h, with both remaining elevated after 6 h (p < 0.05). LM increased plasma [NO3 -] (p < 0.05) but did not increase plasma [NO2 -] compared to PL (p = 0.177). MAP was lower following the consumption of HL at 4 h and LM at 6 h (p < 0.05). CONCLUSION: Inorganic NO3 - consumption is the critical factor in elevating plasma [NO3 -] and [NO2 -]; however, both NO2 - and NO3 - show potential to reduce MAP. The known reduction of systolic blood pressure (SBP)/diastolic blood pressure (DBP) following NO3 - supplementation was not observed, making it unclear if NO2 - contributes to a reduction in SBP/DBP alongside NO3 -.Item Symbiosal® and lowering of blood pressure and reduced risk of hypertension: evaluation of a health claim pursuant to Article 14 of Regulation (EC) No 1924/2006(John Wiley and Sons Ltd on behalf of European Food Safety Authority, 2018-07-25) EFSA Panel on Dietetic Products, Nutrition and Allergies (EFSA NDA Panel); Turck D; Bresson J-L; Burlingame B; Dean T; Fairweather-Tait S; Heinonen M; Hirsch-Ernst KI; Mangelsdorf I; McArdle HJ; Naska A; Neuhäuser-Berthold M; Nowicka G; Pentieva K; Sanz Y; Sjödin A; Stern M; Tomé D; Van Loveren H; Vinceti M; Willatts P; Martin A; Strain SJJ; Siani AFollowing an application from Han-Biotech GmbH, submitted for authorisation of a health claim pursuant to Article 14 of Regulation (EC) No 1924/2006 via the Competent Authority of Germany, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver an opinion on the scientific substantiation of a health claim related to Symbiosal®, lowering of blood pressure and reduced risk of hypertension. The Panel considers that the food, Symbiosal®, which is the subject of the health claim, and the food, table salt, which Symbiosal® should replace, are sufficiently characterised. Lowering of blood pressure is a beneficial physiological effect. Increased blood pressure is a risk factor for hypertension. In weighing the evidence, the Panel took into account that one human study with some methodological limitations showed an effect of Symbiosal® on blood pressure in the context of a self-selected diet with a maximum of 3 g/day added salt. The Panel also took into account that no other human studies in which these results have been replicated were provided, that the animal studies did not support the results of the human study, that no evidence was provided in support of a mechanism by which Symbiosal® could induce a decrease in blood pressure upon oral consumption as compared to table salt in vivo in humans, and the low biological plausibility of the effect observed in the human intervention study. The Panel concludes that a cause and effect relationship has not been established between the consumption of Symbiosal® and lowering of blood pressure.Item Effects of age on blood pressure and heart rate responses to whey protein in younger and older men(John Wiley and Sons, Inc on behalf of The American Geriatrics Society, 2021-05) Giezenaar C; Oberoi A; Jones KL; Horowitz M; Chapman I; Soenen SBACKGROUND: Postprandial falls in blood pressure (BP) are more common in older compared to younger individuals. The effects of protein compared to carbohydrates and fat on postprandial BP, and the relation to gastric emptying rates, are poorly studied. OBJECTIVES: To determine the effects of a whey protein compared to a control drink on systolic BP (SBP) and diastolic BP (DBP), and heart rate (HR) in healthy younger and older men, and to relate these effects to gastric emptying. DESIGN: A pooled analyses of two randomized, double-blind, cross-over studies. SETTING: Two acute clinical intervention studies with identical study design. PARTICIPANTS: Nineteen older (age: 74 ± 1 years, body mass index: 26 ± 1 kg/m2 ) and 13 younger (23 ± 1 years, 24 ± 1 kg/m2 ) healthy men. INTERVENTION: A 70 g/280 kcal whey-protein or control (water with diet cordial, ~2 kcal) drink (450 ml). MEASUREMENTS: BP and HR were assessed with an automated device immediately before and at 3-min intervals after drink ingestion (0-180 min). Gastric emptying of the drinks was measured using 3D ultrasonography (0-180 min). RESULTS: Older versus younger men exhibited a greater fall in SBP (-23 ± 2 vs -15 ± 2 mmHg, p = 0.001) after whey-protein versus control, as BP did not change after the two drinks in younger men (p > 0.05). The nadir in SBP occurred later in the older than younger men (114 ± 11 vs 62 ± 14 min; p < 0.001), with SBP still apparently declining 180 min after whey-protein ingestion in the older men. The magnitude of the rise in HR was greater (p < 0.05) in the younger than older men. CONCLUSION: Following ingestion of 70 g whey protein, healthy older men exhibited a sustained fall in BP, despite an increase in HR, whereas in younger men there was no change in BP. BP may need to be monitored after high protein meals in older people at risk of postprandial hypotension.