Intermittent compression of the calf muscle as a countermeasure to protect blood pressure and brain blood flow in upright posture in older adults

Purpose: Orthostatic hypotension, leading to cerebral hypoperfusion, can result in postural instability and falls in older adults. We determined the efficacy of a novel, intermittent pneumatic compression system, applying pressure around the lower …

Acute effect of moderate-intensity aerobic exercise on cerebral blood flow and cognitive function in young adults: Treadmill vs. cycle ergometer

PURPOSE: This study aimed to compare the acute effects of different types (treadmill vs. cycle) of moderate-intensity aerobic exercise on cerebral blood flow and cognitive function in young adults. METHODS: By a randomized crossover study design, ten …

Altered arterial stiffness, cerebral blood flow and cognitive function in young smokers in response to one-bout of aerobic exercise: Mice vs. hiie

PURPOSE: This study aimed to compare the acute effects of high-intensity interval exercise (HIIE) with moderate-intensity continuous exercise (MICE) on arterial stiffness, cerebral blood flow and cognitive function in young smokers. METHODS: Young …

Cerebral oxygen availability during exercise in COPD patients with cognitive impairment

Insufficient cerebral blood flow regulation to meet increasing metabolic demand during physical exertion could be associated with cognitive impairment. We compared cerebral oxygen availability during exercise in cognitively impaired (CI) to …

Tooth clenching induces abnormal cerebrovascular responses in migraineurs

Prevalence of masticatory parafunctions, such as tooth clenching and grinding, is higher among migraineurs than non-migraineurs, and masticatory dysfunctions may aggravate migraine. Migraine predisposes to cerebrovascular disturbances, possibly due …

Multivitamins and minerals modulate whole-body energy metabolism and cerebral blood-flow during cognitive task performance: A double-blind, randomised, placebo-controlled trial

Background: The brain is by far the most metabolically active organ in the body, with overall energy expenditure and local blood-supply closely related to neural activity. Both energy metabolism and cerebral vaso-dilation are dependent on adequate …

Dietary nitrate modulates cerebral blood flow parameters and cognitive performance in humans: A double-blind, placebo-controlled, crossover investigation

Nitrate derived from vegetables is consumed as part of a normal diet and is reduced endogenously via nitrite to nitric oxide. It has been shown to improve endothelial function, reduce blood pressure and the oxygen cost of sub-maximal exercise, and …

A double-blind, placebo-controlled study evaluating the effects of caffeine and L-theanine both alone and in combination on cerebral blood flow, cognition and mood

Abstract Rationale: Evidence suggests interactive effects of the tea components caffeine and L-theanine on behaviour, yet no data exists exploring the impact of the two on cerebral blood flow (CBF). Objectives: The current placebo-controlled, …

AltitudeOmics: On the consequences of high-altitude acclimatization for the development of fatigue during locomotor exercise in humans

Amann M, Goodall S, Twomey R, Subudhi AW, Lovering AT, Roach RC. AltitudeOmics: on the consequences of high-altitude acclimatization for the development of fatigue during locomotor exercise in humans. J Appl Physiol 115: 634-642, 2013. First …

Middle cerebral O2 delivery during the modified Oxford maneuver increases with sodium nitroprusside and decreases during phenylephrine

The modified Oxford maneuver is the reference standard for assessing arterial baroreflex function. The maneuver comprises a systemic bolus injection of 100 $μ$g sodium nitroprusside (SNP) followed by 150 $μ$g phenylephrine (PE). On the one hand, this …

Effects of acetazolamide and dexamethasone on cerebral hemodynamics in hypoxia

Previous attempts to detect global cerebral hemodynamic differences between those who develop headache, nausea, and fatigue following rapid exposure to hypoxia [acute mountain sickness (AMS)] and those who remain healthy have been inconclusive. In …

Cerebral blood flow and behavioural effects of caffeine in habitual and non-habitual consumers of caffeine: A near infrared spectroscopy study

Caffeine has been shown to modulate cerebral blood flow, with little evidence of tolerance to these effects following habitual use. However, previous studies have focused on caffeine levels much higher than those found in dietary servings and have …

Cerebral blood flow and oxygenation at maximal exercise: The effect of clamping carbon dioxide

During exercise, as end-tidal carbon dioxide (PETCO2) drops after the respiratory compensation point (RCP), so does cerebral blood flow velocity (CBFv) and cerebral oxygenation. This low-flow, low-oxygenation state may limit work capacity. We …

Does cerebral oxygen delivery limit incremental exercise performance?

Previous studies have suggested that a reduction in cerebral oxygen delivery may limit motor drive, particularly in hypoxic conditions, where oxygen transport is impaired. We hypothesized that raising end-tidal PCO 2 (PETCO 2) during incremental …

Thermal effects of mobile phone RF fields on children: A provocation study

The aim of this study was to examine thermal and local blood flow responses in the head area of the preadolescent boys during exposure to radiofrequency (RF) electromagnetic fields produced by a GSM mobile phone. The design was a double-blinded …

Cerebral oxygenation decreases but does not impair performance during self-paced, strenuous exercise

Aim: The reduction in cerebral oxygenation (Cox) is associated with the cessation of exercise during constant work rate and incremental tests to exhaustion. Yet in exercises of this nature, ecological validity is limited due to work rate being either …

Application of ultrasound dilution technology for cardiac output measurement: Cerebral and systemic hemodynamic consequences in a juvenile animal model

Objective: Analysis of cerebral and systemic hemodynamic consequences of ultrasound dilution cardiac output measurements. Design: Prospective, experimental piglet study. Setting: Animal laboratory. SUBJECTS: Nine piglets. INTERVENTIONS: Ultrasound …

Cortical oxygen supply during postural hypotension is further decreased in Alzheimer's disease, but unrelated to cholinesterase-inhibitor use

Cerebrovascular function and structure of the cortical cerebral microvessels are profoundly altered in patients with Alzheimer's disease (AD). The functional hemodynamic consequences of such changes, however, remain essentially unknown. …

Effect of ventilation on cerebral oxygenation during exercise: Insights from canonical correlation

We tested hypothesis that cerebral deoxygenation near maximal exercise intensity is mediated by hyperventilation, via hypocapnia-induced reductions in cerebral blood flow, by utilizing canonical correlation analysis (CCA) to determine the relative …

Cerebrovascular responses to incremental exercise during hypobaric hypoxia: Effect of oxygenation on maximal performance

We sought to describe cerebrovascular responses to incremental exercise and test the hypothesis that changes in cerebral oxygenation influence maximal performance. Eleven men cycled in three conditions: 1) sea level (SL); 2) acute hypoxia [AH; …