Effects of water drinking on cardiovascular responses to supine exercise and on orthostatic hypotension after exercise in pure autonomic failure

Influence of Fluid Ingestion on Heart Rate, Cardiac Autonomic Modulation and Blood Pressure in Response to Physical Exercise: A Systematic Review with Meta-Analysis and Meta-Regression

A systematic review was undertaken to investigate the involvement of hydration in heart rate (HR), HR variability (HRV) and diastolic (DBP) and systolic (SBP) blood pressure in response to exercise. Data synthesis: The EMBASE, MEDLINE, Cochrane Library, CINAHL, LILACS and Web of Science databases were searched. In total, 977 studies were recognized, but only 36 were included after final screening (33 studies in meta-analysis). This study includes randomized controlled trials (RCTs) and non-RCTs with subjects > 18 years old. The hydration group consumed water or isotonic drinks, while the control group did not ingest liquids. For the hydration protocol (before, during and after exercise), the HR values during the exercise were lower compared to the controls (-6.20 bpm, 95%CI: -8.69; -3.71). In the subgroup analysis, "water ingested before and during exercise" showed lower increases in HR during exercise (-6.20, 95%CI: 11.70 to -0.71), as did "water was ingested only during exercise" (-6.12, 95%CI: -9.35 to -2.89). Water intake during exercise only revealed a trend of avoiding greater increases in HR during exercise (-4,60, 95%CI: -9.41 to 0.22), although these values were not significantly different (p = 0.06) from those of the control. "Isotonic intake during exercise" showed lower HRs than the control (-7.23 bpm, 95% CI: -11.68 to -2.79). The HRV values following the exercise were higher in the hydration protocol (SMD = 0.48, 95%CI: 0.30 to 0.67). The values of the SBP were higher than those of the controls (2.25 mmHg, 95%CI: 0.08 to 4.42). Conclusions: Hydration-attenuated exercise-induced increases in HR during exercise, improved autonomic recovery via the acceleration of cardiac vagal modulation in response to exercise and caused a modest increase in SBP values, but did not exert effects on DBP following exercise.

Effectiveness of non-pharmacological interventions to treat orthostatic hypotension in elderly people and people with a neurological condition: a systematic review

OBJECTIVE

The objective of this review was to summarize the best available evidence regarding the effectiveness of non-pharmacological interventions to treat orthostatic hypotension (OH) in elderly people and people with a neurological condition.

INTRODUCTION

Orthostatic hypotension is common in elderly people and people with a neurological condition and can interfere with or limit rehabilitation. Non-pharmacological interventions to treat OH could allow for longer and earlier mobilization, which is recommended in national clinical guidelines for rehabilitation in the acute or sub-acute phase following stroke or other neurological conditions.

INCLUSION CRITERIA

The review considered people aged 50 years and older, and people aged 18 years and elderly people with a neurological condition. Non-pharmacological interventions to treat OH included compression garments, neuromuscular stimulation, physical counter-maneuvers, aerobic or resistance exercises, sleeping with head tilted up, increasing fluid and salt intake, and timing and size of meals. The comparator was usual care, no intervention, pharmacological interventions, or other non-pharmacological interventions. Outcome measures included systolic blood pressure, diastolic blood pressure, heart rate, cerebral blood flow, observed/perceived symptoms, duration of standing or sitting in minutes, tolerance of therapy, functional ability, and adverse events/effects.

METHODS

Databases for published and unpublished studies available in English up to April 2018 with no lower date limit were searched. Critical appraisal was conducted using standardized instruments from JBI. Data were extracted using standardized tools designed for quantitative studies. Where appropriate, studies were included in a meta-analysis; otherwise, data were presented in a narrative form due to heterogeneity.

RESULTS

Forty-three studies - a combination of randomized controlled trials (n = 13), quasi-experimental studies (n = 28), a case control study (n = 1), and a case report (n = 1) - with 1069 participants were included. Meta-analyses of three interventions (resistance exercise, electrical stimulation, and lower limb compression bandaging) showed no significant effect of these interventions. Results from individual studies indicated physical maneuvers such as leg crossing, leg muscle pumping/contractions, and bending forward improved orthostatic hypotension. Abdominal compression improved OH. Sleeping with head up in combination with pharmacological treatment was more effective than sleeping with head up alone. Eating smaller, more frequent meals was effective. Drinking 480 mL of water increased blood pressure.

CONCLUSIONS

The review found mixed results for the effectiveness of non-pharmacological interventions to treat OH in people aged 50 years and older, and people with a neurological condition. There are several non-pharmacological interventions that may be effective in treating OH, but not all have resulted in clinically meaningful changes in outcome. Some may not be suitable for people with moderate to severe disability; therefore, it is important for clinicians to consider the patient's abilities and impairments when considering which non-pharmacological interventions to implement.

Autonomic dysfunction: Diagnosis and management

The autonomic nervous system is designed to maintain physiologic homeostasis. Its widespread connections make it vulnerable to disruption by many disease processes including primary etiologies such as Parkinson's disease, multiple system atrophy, dementia with Lewy bodies, and pure autonomic failure and secondary etiologies such as diabetes mellitus, amyloidosis, and immune-mediated illnesses. The result is numerous symptoms involving the cardiovascular, gastrointestinal, and urogenital systems. Patients with autonomic dysfunction (AUD) often have peripheral and/or cardiac denervation leading to impairment of the baroreflex, which is known to play a major role in determining hemodynamic outcome during orthostatic stress and low cardiac output states. Heart rate and plasma norepinephrine responses to orthostatic stress are helpful in diagnosing impairment of the baroreflex in patients with orthostatic hypotension (OH) and suspected AUD. Similarly, cardiac sympathetic denervation diagnosed with MIBG scintigraphy or ¹⁸F-DA PET scanning has also been shown to be helpful in distinguishing preganglionic from postganglionic involvement and in diagnosing early stages of neurodegenerative diseases. In this chapter, we review the causes of AUD, the pathophysiology and resulting cardiovascular manifestations with emphasis on the diagnosis and treatment of OH.

Evidence-based treatment of neurogenic orthostatic hypotension and related symptoms

Neurogenic orthostatic hypotension, postprandial hypotension and exercise-induced hypotension are common features of cardiovascular autonomic failure. Despite the serious impact on patient’s quality of life, evidence-based guidelines for non-pharmacological and pharmacological management are lacking at present. Here, we provide a systematic review of the literature on therapeutic options for neurogenic orthostatic hypotension and related symptoms with evidence-based recommendations according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE). Patient’s education and non-pharmacological measures remain essential, with strong recommendation for use of abdominal binders. Based on quality of evidence and safety issues, midodrine and droxidopa reach a strong recommendation level for pharmacological treatment of neurogenic orthostatic hypotension. In selected cases, a range of alternative agents can be considered (fludrocortisone, pyridostigmine, yohimbine, atomoxetine, fluoxetine, ergot alkaloids, ephedrine, phenylpropanolamine, octreotide, indomethacin, ibuprofen, caffeine, methylphenidate and desmopressin), though recommendation strength is weak and quality of evidence is low (atomoxetine, octreotide) or very low (fludrocortisone, pyridostigmine, yohimbine, fluoxetine, ergot alkaloids, ephedrine, phenylpropanolamine, indomethacin, ibuprofen, caffeine, methylphenidate and desmopressin). In case of severe postprandial hypotension, acarbose and octreotide are recommended (strong recommendation, moderate level of evidence). Alternatively, voglibose or caffeine, for which a weak recommendation is available, may be useful.

Management of neurogenic orthostatic hypotension in patients with autonomic failure

The maintenance of blood pressure in the upright position requires intact autonomic cardiovascular reflexes. Diseases that affect the sympathetic innervation of the cardiovascular system result in a sustained fall in blood pressure upon standing (i.e., neurogenic orthostatic hypotension) that can impair the blood supply to the brain and other organs and cause considerable morbidity and mortality. Here we review treatment options for neurogenic orthostatic hypotension and include an algorithm for its management that emphasizes the importance of non-pharmacologic measures and provides guidance on pharmacologic treatment options.

Cardiovascular status of individuals with incomplete spinal cord injury from 7 NeuroRecovery Network rehabilitation centers

OBJECTIVE

To examine cardiovascular (CV) health in a large cohort of individuals with incomplete spinal cord injury (SCI). The CV health parameters of patients were compared based on American Spinal Injury Association Impairment Scale (AIS), neurologic level, sex, central cord syndrome, age, time since injury, Neuromuscular Recovery Scale, and total AIS motor score.

DESIGN

Cross-sectional study.

SETTING

Seven outpatient rehabilitation clinics.

PARTICIPANTS

Individuals (N=350) with incomplete AIS classification C and D were included in this analysis.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Heart rate, systolic and diastolic blood pressure during resting sitting and supine positions and after an orthostatic challenge.

RESULTS

CV parameters were highly variable and significantly differed based on patient position. Neurologic level (cervical, high and low thoracic) and age were most commonly associated with CV parameters where patients classified at the cervical level had the lowest resting CV parameters. After the orthostatic challenge, blood pressure was highest for the low thoracic group, and heart rate for the high thoracic group was higher. Time since SCI was negatively related to blood pressure at rest but not after orthostatic challenge. Men exhibited higher systolic blood pressure than women and lower heart rate. The prevalence of orthostatic hypotension (OH) was 21% and was related to the total motor score and resting seated blood pressures. Cervical injuries had the highest prevalence.

CONCLUSIONS

Resting CV parameters of blood pressure and heart rate are affected by position, age, and neurologic level. OH is more prevalent in cervical injuries, those with lower resting blood pressures and who are lower functioning. Results from this study provide reference for CV parameters for individuals with incomplete SCI. Future research is needed on the impact of exercise on CV parameters.

Acute fluid ingestion in the treatment of orthostatic intolerance - important implications for daily practice

BACKGROUND

Rapid water ingestion improves orthostatic intolerance (OI) in multiple system atrophy (MSA) and postural tachycardia syndrome (PoTS). We compared haemodynamic changes after water and clear soup intake, the latter being a common treatment strategy for OI in daily practice.

METHODS

Seven MSA and seven PoTS patients underwent head-up tilt (HUT) without fluid intake and 30 min after drinking 450 ml of water and clear soup, respectively. All patients suffered from moderate to severe OI because of neurogenic orthostatic hypotension (OH) and excessive orthostatic heart rate (HR) increase, respectively. Beat-to-beat cardiovascular indices were measured non-invasively.

RESULTS

In MSA, HUT had to be terminated prematurely in 2/7 patients after water, but in 6/7 after clear soup. At 3 min of HUT, there was an increase in blood pressure of 15.7(8.2)/8.3(2.3) mmHg after water, but a decrease of 11.6(18.9)/8.1(9.2) mmHg after clear soup (P < 0.05). In PoTS, HUT could always be completed for 10 min, but OI subjectively improved after both water and clear soup. The attenuation of excessive orthostatic HR increase did not differ significantly after water and clear soup drinking.

CONCLUSIONS

In MSA, clear soup cannot substitute water for eliciting a pressor effect, but even worsens OI after rapid ingestion. In PoTS, acute water and clear soup intake both result in improvement of OI. These findings cannot solely be explained by difference in osmolarity but may reflect some degree of superimposed postprandial hypotension in widespread autonomic failure in MSA compared to the mild and limited autonomic dysfunction in PoTS.