Luana Bernardi

Universidade Estadual do Centro-Oeste | UNICENTRO · Departamento de Nutrição

Background Hyperglycemia-induced oxidative stress is a well-established pathological mediator of vascular complications in diabetes. We assessed plasma oxidant and antioxidant levels in response to acute and chronic hyperglycemia in relation to vascular stiffness and varying degrees of kidney disease in type 1 diabetes individuals. Methods The acu...

In light of theories postulating a role for music in forming emotional and social bonds, here we investigated whether endogenous rhythms synchronize between multiple individuals when listening to music. Cardiovascular and respiratory recordings were taken from multiple individuals (musically trained or music-naïve) simultaneously, at rest and durin...

The effects of meditation on arterial and tissue oxygenation are unknown and difficult to assess because respiration is often altered, directly or indirectly, during meditation practice. Thus, changes in respiration may affect cardiovascular responses independently from meditation. In this study, we aim to isolate the specific effect of meditation...

Hyperoxia and slow breathing acutely improve autonomic function in type-1 diabetes. However, their effects on arterial function may reveal different mechanisms, perhaps potentially useful. To test the effects of oxygen and slow breathing we measured arterial function (augmentation index, pulse wave velocity), baroreflex sensitivity (BRS) and oxygen...

Objetivo: Analisar os fatores associados ao Aleitamento Materno Exclusivo (AME) em criancas menores de seis meses de vida em Guarapuava-PR. Metodologia : Foram analisados dados das criancas menores de seis meses de vida que participaram da Campanha Nacional de Vacinacao contra Poliomielite 2012, em Guarapuava-PR. A coleta ocorreu por aplicacao de q...

Autonomic dysfunction is a frequent and relevant complication of diabetes mellitus, as it is associated with increased morbidity and mortality. In addition, it is today considered as predictive of the most severe diabetic complications, like nephropathy and retinopathy. The classical methods of screening are the cardiovascular reflex tests and were...

Purpose: The present study evaluated the effects of a pre-acclimatization program comprising 7 passive 1-hour exposures to 4,500 m normobaric hypoxia on the prevalence and severity of acute mountain sickness (AMS) during a subsequent exposure to real high altitude in persons susceptible to AMS. Methods: The project was designed as a randomized c...

Background: The systemic impact of intra-abdominal pressure (IAP) and/or changes in carbon dioxide (CO 2) during laparoscopy are not yet well defined. Changes in brain oxygenation have been reported as a possible cause of cerebral hypotension and perfusion. The side effects of anaesthesia could also be involved in these changes, especially in chil...

Aims The aim of this study was to describe the head-up tilt (HUT) test and carotid sinus massage (CSM) responses, and the occurrence of syncope with coughing during HUT in a large cohort of patients. Methods and results A total of 5133 HUT were retrospectively analysed to identify patients with cough syncope. Head-up tilt followed by CSM were perf...

Although oxygen is commonly used to treat various medical conditions, it has recently been shown to worsen vascular function (arterial stiffness) in healthy volunteers and even more in patients in whom vascular function might already be impaired. The effects of oxygen on arterial function in patients with type 1 diabetes (T1D) are unknown, although...

Background: It is not known whether parasympathetic outflow simultaneously acts on bronchial tone and cardiovascular system waxing and waning both systems in parallel, or, alternatively, whether the regulation is more dependent on local factors and therefore independent on each system. The aim of this study was to evaluate the simultaneous effect...

Controlled slow breathing (at 6/min, a rate frequently adopted during yoga practice) can benefit cardiovascular function, including responses to hypoxia. We tested the neural substrates of cardiorespiratory control in humans during volitional controlled breathing and hypoxic challenge using functional magnetic resonance imaging (fMRI). Twenty healt...

Cardiovascular autonomic dysfunction, evaluated as baroreflex sensitivity (BRS), could be acutely corrected by slow breathing or oxygen administration in patients with type 1 diabetes, thus suggesting a functional component of the disorder. We tested this hypothesis in patients with the type 2 diabetes with or without renal impairment. Twenty-six p...

Background and aims Similarly to diabetes type 2, patients with obesity show insulin resistance, autonomic and vascular abnormalities associated with increased morbidity and mortality. We tested whether arterial dysfunction in obese children may have a functional nature, reversible with appropriate interventions (eg by reduction of sympathetic acti...

We tested whether pre-assigned arm movements performed in a group setting spontaneously synchronized and whether synchronization extended to heart and respiratory rhythms. We monitored arm movements, respiration and electrocardiogram at rest and during spontaneous, music and metronome-associated arm-swinging. No directions were given on whether or...

Introduction and Aims: Diabetes mellitus type-2 (T2DM) is a metabolic disorder leading to diabetic nephropathy (DN) responsible for approximately 35% chronic renal failure (CRF) on waiting list of renal transplantation (RT). RT is a well accepted therapy for these patients however life-long immunosuppression mandatory to prevent the allograft rejec...

Current opinion is that a vagal stimulation is beneficial for the cardiovascular apparatus but also causes airflow obstruction. The aim of this study was to examine this paradox. By using the within-breath Forced Oscillation Technique, inspiratory resistance and reactance at 5 Hz (R5 and X5, respectively) and cardio-vascular activity can be simulta...

Alterations in cardiovascular and respiratory reflexes in diabetes are probably one of the first applications of heart rate variability in clinical medicine. Despite significant progress in diabetes care, these abnormalities are still considered the result of anatomical neural damage. Recent research from our group showed that what had been called...

Objective:Type 2 diabetes is associated with impaired respiratory and cardiovascular control. Physical exercise training is a well-established tool in the treatment of diabetes. However, effects of short-term exercise training on respiratory control in diabetes are unknown. Thus, we examined the effects of 4 weeks of exercise training (high intensi...

Hypoxemia is common in diabetes, and reflex responses to hypoxia are blunted. These abnormalities could lead to cardiovascular/renal complications. Interval hypoxia (5-6 short periods of hypoxia each day over 1-3 weeks, IH), was successfully used to improve the adaptation to hypoxia in COPD. We tested whether IH over one day could initiate a long-l...

Slow breathing increases cardiac-vagal baroreflex sensitivity (BRS), improves oxygen saturation, lowers blood pressure, and reduces anxiety. Within the yoga tradition slow breathing is often paired with a contraction of the glottis muscles. This resistance breath "ujjayi" is performed at various rates and ratios of inspiration/expiration. To test w...

OBJECTIVE Hypoxia may cause functional autonomic imbalance in diabetes. Intermittent hypoxia (IH), a technique improving the adaptation to hypoxia, might improve cardiorespiratory reflexes and, ultimately, blood glucose concentrations in patients with type 2 diabetes. We tested whether a single bout of IH could initiate a long-lasting response pote...

Yoga was intended for spiritual evolution [1], but increasingly nowadays it is used for its incidental benefits such as stress reduction and managing lifestyle related disorders. Despite its Indian origin, the number of yoga practitioners in Western society is growing: in the United States, for example, a national survey showed that 6.1% of the adu...

Intermittent hypoxic exposure (IHE) has been shown to induce aspects of altitude acclimatization which affect ventilatory, cardiovascular and metabolic responses during exercise in normoxia and hypoxia. However, knowledge on altitude-dependent effects and possible interactions remains scarce. Therefore, we determined the effects of IHE on cardiores...

Background: Predicting the occurrence of syncope in advance during tilt test could be useful to prepare the medical staff in preventing complications connected with this procedure, particularly in patients with no pre-syncopal symptoms. Our objective was to develop a simple algorithm able to predict the onset of neuromediated syncope during the ti...

The Cardiovascular Autonomic Neuropathy (CAN) Subcommittee of the Toronto Consensus Panel on Diabetic Neuropathy worked to update CAN guidelines, with regard to epidemiology, clinical impact, diagnosis, usefulness of CAN testing, and management. CAN is the impairment of cardiovascular autonomic control in the setting of diabetes after exclusion of...

This consensus document provides evidence-based guidelines regarding the evaluation of diabetic cardiovascular autonomic neuropathy (CAN) for human research studies; the guidelines are the result of the work of the CAN Subcommittee of the Toronto Diabetic Neuropathy Expert Group. The subcommittee critically reviewed the limitations and strengths of...

We have recently demonstrated that early autonomic dysfunction, defined as low baroreflex sensitivity (BRS), could be functional and reversible. However, potential temporal changes in BRS have not yet been addressed by longitudinal studies in type 1 diabetes. Moreover, it is not known whether low BRS predisposes to hypertension or other nonfatal di...

The relationship between work rate (WR) and its tolerable duration (t(LIM)) has not been investigated at high altitude (HA). At HA (5050 m) and at sea level (SL), six subjects therefore performed symptom-limited cycle-ergometry: an incremental test (IET) and three constant-WR tests (% of IET WR(max), HA and SL respectively: WR(1) 70±8%, 74±7%; WR(2...

Cardiovascular autonomic neuropathy is associated with increased morbidity in patients with type 1 diabetes. Although it is conventionally considered to be an organic, irreversible disorder, we previously demonstrated in patients with short-duration type 1 diabetes that reduced baroreflex sensitivity (BRS) could be corrected by slow, deep breathing...

We hypothesised that the blunted baroreflex sensitivity (BRS) typical of type 1 diabetes is caused by a higher degree of tissue hypoxia in diabetes, and tested whether oxygen increased BRS and ventilation less, equally or more than in healthy control participants (the latter suggesting higher tissue hypoxia). In addition, we also considered the pos...

Baroreflex sensitivity (BRS) is an important prognostic index in cardiovascular diseases, however, its use is complicated by different methods difficult to compare and standardize, often providing conflicting results. We tested whether the simple ratio of RR interval to systolic blood pressure global variabilities (assessed by standard deviations)...

Although considered mainly a random function, postural sway is influenced by physiological factors such as respiration. A direct effect of the autonomic nervous system (ANS) on posture has never been demonstrated. To test this hypothesis, we used a pure motion-independent autonomic stimulus (neck suction) to modulate the carotid baroreceptors on a...

While patients with type 1 diabetes (T1D) are known to suffer from early cardiovascular disease (CVD), we examined associations between arterial stiffness and diabetic complications in a large patient group with T1D. This study included 807 subjects (622 T1D and 185 healthy volunteers (age 40.6 ± 0.7 versus 41.6 ± 1.2 years; P = NS)). Arterial stif...

Preceding the joint meeting of the 19th annual Diabetic Neuropathy Study Group of the European Association for the Study of Diabetes (NEURODIAB) and the 8th International Symposium on Diabetic Neuropathy in Toronto, Canada, 13-18 October 2009, expert panels were convened to provide updates on classification, definitions, diagnostic criteria, and tr...

Reactions to music are considered subjective, but previous studies suggested that cardiorespiratory variables increase with faster tempo independent of individual preference. We tested whether compositions characterized by variable emphasis could produce parallel instantaneous cardiovascular/respiratory responses and whether these changes mirrored...

Cardiac autonomic neuropathy is associated with increased morbidity and mortality rates in patients with type 1 diabetes. The prevalence of early autonomic abnormalities is relatively high compared with the frequency of manifest clinical abnormalities. Thus, early autonomic dysfunction could to some extent be functional and might lead to an organic...

Chronic obstructive pulmonary disease (COPD) is associated with cardiac autonomic nervous system dysregulation. This study evaluates the effects of interval hypoxic training on cardiovascular and respiratory control in patients with mild COPD. In 18 eucapnic normoxic mild COPD patients (age 51.7 +/- 2.4 years, mean +/- SEM), randomly assigned to ei...

Yoga-derived breathing has been reported to improve gas exchange in patients with chronic heart failure and in participants exposed to high-altitude hypoxia. We investigated the tolerability and effect of yoga breathing on ventilatory pattern and oxygenation in patients with chronic obstructive pulmonary disease (COPD). Patients with COPD (N = 11,...

The effects of repeated short-term hypoxia on exercise tolerance in patients at risk for, or with mild COPD were investigated. Eighteen patients (10 males, 8 females; 33-72 years) were randomly assigned in a double-blind fashion to receive 15 sessions of intermittent hypoxia (FiO(2): 0.15-0.12) or normoxia within 3 weeks. Three weeks of intermitten...

Patients with chronic obstructive pulmonary disease (COPD) may develop hypercapnia and hypoxia, two main determinants of cerebral blood flow. The current authors tested whether cerebrovascular regulation was altered in mild COPD, modified by manoeuvres acutely improving autonomic cardiovascular modulation or influenced by smoking habit. In 15 eucap...

Neurohumoral activation has been shown to be present in hypoxic patients with chronic obstructive pulmonary disease (COPD). The aims of the present study were to investigate whether there is sympathetic activation in COPD patients in the absence of hypoxia and whether slow breathing has an impact on sympathoexcitation and baroreflex sensitivity. Ef...

To analyse the influence of breathing activity on cerebrovascular dynamics during presyncope. Retrospective study. University hospital. 38 subjects developing neurocardiogenic syncope (syncope group), and 61 age-matched control subjects with negative tilt. Middle cerebral artery mean blood flow velocity (MCFV), continuous non-invasive blood pressur...

To assess the effects of acute exposure to simulated high altitude on baroreflex control of mean cerebral blood flow velocity (MCFV). We compared beat-to-beat changes in RR interval, arterial blood pressure, mean MCFV (by transcranial Doppler velocimetry in the middle cerebral artery), end-tidal CO2, oxygen saturation and respiration in 19 healthy...

Exercise performance in heart-transplanted patients increases with respect to pre-transplantation but remains subnormal, and it does not improve with time after surgery. Possible causes include persisting denervation, and sympathetic vasoconstriction inducing functional vascular abnormalities that prevent adequate increase in blood flow to the exer...

Yoga induces long-term changes in respiratory function and control. We tested whether it represents a successful strategy for high-altitude adaptation. We compared ventilatory, cardiovascular and hematological parameters in: 12 Caucasian yoga trainees and 12 control sea-level residents, at baseline and after 2-week exposure to high altitude (Pyrami...

Primary effect of hypobaric hypoxia on the circulation is a direct vasodilatory effect on the peripheral circulation, which is normally prevented by a sympathetic-induced vasoconstriction. Most of the clinical methods for testing the baroreflex sensitivity only evaluate the cardiac-vagal branch of the baroreflex, but at altitude it is also of impor...

The increase in peripheral chemoreflex sensitivity in patients with obstructive sleep apnea (OSA) is associated with activation of autonomic nervous system and hemodynamic responses. Nasal CPAP (nCPAP) is an effective treatment for OSA, but little is known on its effect on chemoreflex sensitivity. To assess the effect of nCPAP treatment or placebo...

To assess the potential clinical use, particularly in modulating stress, of changes in the cardiovascular and respiratory systems induced by music, specifically tempo, rhythm, melodic structure, pause, individual preference, habituation, order effect of presentation, and previous musical training. Measurement of cardiovascular and respiratory varia...

A very high ventilatory response to hypoxia is believed necessary to reach extreme altitude without oxygen. Alternatively, the excessive ventilation could be counterproductive by exhausting the ventilatory reserve early on. To test these alternatives, 11 elite climbers (2004 Everest-K2 Italian Expedition) were evaluated as follows: 1) at sea level,...

It is widely recognised that during exercise vagal heart rate control is markedly impaired but blood pressure control may or may not be retained. We hypothesised that this uncertainty arose from the differing responses of the vagus (fast) and sympathetic (slow) arms of the autonomic effectors, and to differing sympatho-vagal balance at different ex...

We investigated the interaction between hypoxia and hypercapnia on ventilation and on cerebro-cardio-vascular control. A group of 12 healthy subjects performed rebreathing tests to determine the ventilatory response to hypoxia, at different levels of carbon dioxide (CO(2)), and to normoxic hypercapnia. Oxygen saturation (SaO(2)), end-tidal CO(2) (e...

Sympathetic hyperactivity and parasympathetic withdrawal may cause and sustain hypertension. This autonomic imbalance is in turn related to a reduced or reset arterial baroreflex sensitivity and chemoreflex-induced hyperventilation. Slow breathing at 6 breaths/min increases baroreflex sensitivity and reduces sympathetic activity and chemoreflex act...

Respiration is a powerful modulator of heart rate variability, and of baro- or chemo-reflex sensitivity. This occurs via a mechanical effect of breathing that synchronizes all cardiovascular variables at the respiratory rhythm, particularly when this occurs at a particular slow rate coincident with the Mayer waves in arterial pressure (approximatel...

This is an international consensus statement of an ad hoc committee formed by the International Society for Mountain Medicine (ISMM) at the VI World Congress on Mountain Medicine and High Altitude Physiology (Xining, China; 2004) and represents the committee's interpretation of the current knowledge with regard to the most common chronic and subacu...

This is an international consensus statement of an ad hoc committee formed by the International Society for Mountain Medicine (ISMM) at the VI World Congress on Mountain Medicine and High Altitude Physiology (Xining, China; 2004) and represents the committee's interpretation of the current knowledge with regard to the most common chronic and subacu...

To assess the possible abnormalities in the baroreflex modulation of both the heart and the arterial vasculature, in order to better evaluate the role of baroreflex abnormalities in the generation of the cardiovascular symptoms and complications affecting the familial dysautonomia (FD) patient. Twenty-one FD patients and 22 controls underwent 3 min...

Headache is common in Cerro de Pasco (CP), Peru (altitude 4338 m) and was present in all patients with chronic mountain sickness (CMS) in CP reported here. Forty-seven percent of inhabitants report headache. Twenty-four percent of men have migraine with aura, with an average of 65 attacks a year. We assessed vasoreactivity of the cerebral vessels t...

To determine whether nocturnal hypoxaemia contributes to the excessive erythrocytosis (EE) in Andean natives, standard polysomnographies were performed in 10 patients with EE and in 10 controls (mean haematocrit 76.6±1.3% and 54.4±0.8%, respectively) living at an altitude of 4,380 m. In addition, the effect of O 2 administration for 1 h prior to sl...

Left and right carotid baroreflex afferents participate in generating the spontaneous variability of heart rate (HR), arterial pressure (AP), and muscle sympathetic nerve activity (MSNA), but the relative contribution of each side is unclear. Pathophysiological conditions unilaterally affecting carotid baroreceptor function might result in abnormal...

Chronic mountain sickness (CMS), a maladaptation syndrome to chronic hypoxia, occurs in the Andes. Gene expression differences in Andeans could explain adaptation and maladaptation to hypoxia, both of which are relevant to neurology at sea level. Expression of genes responsive to cellular oxygen concentration, hypoxia-inducible factor-1alpha (HIF-1...