Sustained Handgrip Test Research Articles

Correlation to Serum Ionized Calcium and Magnesium Concentration with Sympathetic Nerve Functions in Type 2 Diabetes Mellitus

Background : In type 2 DM, a metabolic disorder causes disturbances of different metabolic processes of the body including electrolyte imbalance. Therefore changes in serum level of Ca2+ and Mg2+ may have some relationship to the occurrence of neuropathy. Objective : The study has been designed to observe the sympathetic nerve function status in type 2 diabetic subjects in order to assess the relationship between serum ionized calcium & magnesium. Study design : This cross section study was carried out in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh. Forty seven type 2 diabetic subjects were included in two groups. Group B consisted of 25 recently diagnosed diabetic subjects aged 40-68 years and group C consisted of 22 subjects having duration of diabetes for 10-20 years. Twenty five (25) age and BMI matched healthy subjects were included in group A (non-diabetic) for control. Methods : Sympathetic nerve function were assessed by two simple non-invasive cardiovascular reflex tests. These were systolic blood pressure, response to lying to standing up and diastolic blood pressure response to distain hand grip test. Ionized serum calcium and magnesium were measured by ion sensitive electrode method using NOVA electrode. Data were analyzed by ‘t’ test, Pearson’s correlation co-efficient. Results: Serum ionized calcium levels were significantly higher in both the diabetic group B (P<0.001) and C (P<0.001) than that of control group A. Serum ionized magnesium level was significantly higher in diabetic group C (P<0.001) compared to that of control group A. Pearson’s correlation of ionized calcium and magnesium with sympathetic nerve function parameters were done. Statistically significant relation was found in group B between sustained hand grip test with ionized calcium and in group C between systolic blood pressure response to standing with ionized magnesium. Conclusion : Serum ionized calcium & magnesium level was increased in type 2 diabetic patients irrespective of duration and some correlation was found with sympathetic nerve function parameters DOI: http://dx.doi.org/10.3329/updcj.v3i2.17991 Update Dent. Coll. j: 2013; 3 (2): 03-08

A Comparative Study of Cardiovascular Autonomic Function Tests in Yoga Practitioners and Controls

Background: In the present age, a great emphasis is being laid on the practice of yogic postures as a form of highly effective physical exercise for keeping the body healthy and also for the control of disease process. Rhythmic breathing controls the mind, lungs and heart which are located in the thoracic cage and are under the control of autonomic nervous system. The aim of this study was to evaluate the cardiovascular autonomic function tests among yoga practitioners. Method: 75 healthy volunteers (aged 18-31 years)were divided in to three groups; the first two yoga groups ( each group ,n=25 ) consisted of subjects who were practicing the yoga (pranayama and suryanamaskarams) for less than 2 years and more than 2 years, respectively and the third group was controls (n=25). Autonomic function tests were performed for both sympathetic and parasympathetic activity ,which include deep breathing test, valsalva maneuver, heart rate response to standing posture (30:15 ratio) , orthostatic hypotension test and sustained hand grip test. Results: The statistics showed a significant value for heart rate variability , 30:15 ratio ,hand grip test, othrostatic hypotension test and valsalva ratio in group 1 and 2 yoga practitioners (p<0.05) than in controls. But no significant difference observed in terms of resting heart rate in all groups. The overall ewing's autonomic dysfunction score was high in controls compared to yoga practicing subjects ((p<0.05). Conclusion: It is evident that yoga develops an ability to control cardiovascular autonomic functions and would prepare the body to overcome stress by modulating and optimizing sympathetic activities.

The effect of smoking on the cardiovascular autonomic functions: a cross sectional study.

Smoking is a worldwide major cause of preventable morbidity and mortality. Smoking affects the cardiovascular system by several mechanisms. The present study was planned to study the effect of smoking on the cardiovascular autonomic functions among smokers. Hundred male subjects who were in the age group of 25 to 40 years, who included 50 smokers and 50 non - smokers who formed the control group were selected for the present study. The participant subjects were selected from among the staff members, residents and the patients from the routine OPD. Prior informed written consents were obtained from them after explaining to them, the procedure and the purpose of the study tests. The Cardiovascular Autonomic Function Tests were assessed by using a CANWIN AUTONOMIC ANALYSER which was available in the department. After applying the 'Z'-test for the difference between the two sample means, it was observed that there was a highly significant difference between the mean values of the para-sympathetic function tests among the smokers and the non - smokers (i.e. p<0.01) The Resting Heart Rate had significantly increased and the Expiration: Inspiration Ratio, the 30:15 Ratio (Response to standing) and the Valsalva Ratio had significantly decreased in the smokers as compared to those in the non - smokers. After applying the 'Z'-test for the difference between the two sample means, it was observed that there was no significant difference between the mean values of the Postural hypotension test (i.e. p>0.05) and that there was a highly significant difference between the mean values of the Sustained handgrip test in the smokers and the non - smokers (i.e. p<0.01).

Prevalence and pattern of cardiac autonomic dysfunction in newly detected type 2 diabetes mellitus

Cardiac autonomic functions were assessed in 145 consecutive recently detected type 2 diabetics. Ninety-nine healthy persons served as controls. Criteria for normalcy were, heart rate variation during deep breathing ≥15 beats/min, deep breathing expiratory to inspiratory R–R ratio ≥1.21, Valsalva ratio ≥1.21, sustained handgrip test ≥16 mm of mercury, cold pressor test ≥10, BP response to standing ≤10 mm of mercury and 30:15 R–R ratio on standing ≥1.04. An abnormal test was defined as the above parameters being <10 beats/min, <1.21, <1.21, ≤10 mm of mercury, <10, ≥30 mm of mercury and ≤1.0, respectively. A borderline test was defined as, heart rate variation during deep breathing 11–14, sustained handgrip test 11–15 mm of mercury, BP response to standing 11–29 mm of mercury and 30:15 R–R ratio on standing 1.01–1.03. Parasympathetic dysfunction was found in 44.2% and sympathetic dysfunction in 51.9% diabetics. Among healthy controls, these figures were 11.9% and 22.1%, respectively. Cardiac autonomic function was normal in 7.8% patients and 32.5% healthy controls.

Relative Kidney Weight and Renal Histological Study: Amelioration by Nigella Sativa Linn. (Kalajira) of Gentamiein-induced Nephrotoxicity in Rats

The study was designed to observe the sympathetic nerve Auction status in recently diagnosed and long duration (10-20 yeses) type 2 diabetic subjects in order so assess whether the duration of diabetes has any temente on the sympathetic nerve filmdom The present study was rurried out also to obtain a base line data in the form of a set of nomad reference values of cardiosracular reflex test parameters in a seleaed group of adult Bangladeshi population. For this purpose 47 type 2 diabetic subjects were included in two groups, group A consisted 425 recently diagnosed diabetic subjects and group B consisted of 22 subjects having duration of diabetes for 10.20 years. Beenty floe age and BM! matched healthy subjects were included hi group C (non-diabetic) for control and also to observe the baseline data. Sympathetic nerve firriction was assessed by two simple noroin cardiovascular rdiovascular reflex tests. Tests sore sustained handgrip tests and blood pressure response to standing. The normal or reference values obtained from the non-diabetic subjects of the present study were compared to those of published reference values of different population around the world and no apparent differences were observed. Glycaemic status of the diabetic subjects were more or less controlled. Cardiovascular reflex rest for sympathetic Anchor; were found to be significantly affected in long duration diabetic group hi comparison to control group and recently diagnosed diabetic group. Front this. tudy it is concluded that sympathetic nerve finiction seems to be affected at the sante glycaemic status in longer duration of diabee.

Coronary flow reserve, insulin resistance and blood pressure response to standing in patients with normoglycaemia: is there a relationship?

To establish the relationships between coronary flow reserve, cardiovascular autonomic function, and insulin resistance characterized by the homeostasis model assessment insulin resistance score in patients with normal carbohydrate metabolism according to the World Health Organization (WHO) and American Diabetes Association (ADA) criteria, and with morphologically normal epicardial coronary arteries. Twenty-five patients [12 women and 13 men, mean (sd) age: 53 +/- 11 years] with normal coronary angiography were enrolled into the study. Coronary flow reserve was measured during stress transoesophageal echocardiography. Autonomic dysfunction was assessed by means of five standard cardiovascular reflex tests. The fasting serum glucose and insulin levels were determined and the homeostasis assessment model insulin resistance score was calculated. In patients with normal carbohydrate metabolism, negative correlations were observed between the coronary flow reserve and both the serum insulin level (r = -0.445, P = 0.026) and the homeostasis assessment model insulin resistance score (r = -0.449, P = 0.024). The systolic blood pressure response to standing also correlated with the coronary flow reserve (r = -0.519, P = 0.011). The heart rate response to deep breathing, the Valsalva ratio, the 30/15 ratio and the sustained handgrip test results were not correlated with the coronary flow reserve. Our data suggest the possible role of insulin resistance and early sympathetic nerve dysfunction in the development of decreased coronary flow reserve in patients without diabetes mellitus or impaired glucose tolerance.

Early sympathetic hyperactivity in Huntington's disease

To investigate whether Huntington's disease (HD) affects autonomic nervous system (ANS) functioning 33 subjects with positive genetic test results were studied. The subjects were classified according to Shoulson and Fahn (S&F) HD disability scale into three subgroups: subgroup 1 (eight asymptomatic gene carriers), subgroup 2 (13 mildly disabled HD patients) and subgroup 3 (eight moderately and four severely disabled HD patients). A battery of cardiovascular autonomic tests (Valsalva maneuver, deep breathing test, sustained handgrip test, orthostatic test) and the spectral analysis of heart rate variability (HRV) were performed. The results were compared with a group of matched controls. In subgroup 1, there was a higher power of low-frequency band (LFB) (P < 0.05). In subgroup 2 a higher power of LFB was detected, LFB/high-frequency band (HFB) coefficient was increased and the blood pressure response to sustained handgrip was elevated (P < 0.05). Subgroup 3 showed significantly lower blood pressure response to sustained handgrip, lower respiratory (P < 0.05) and orthostatic ratio (P < 0.01). Our results suggest that sympathetic hyperfunction is present in asymptomatic gene carriers and mildly disabled HD patients. Contrary to that, ANS hypofunction was found in advanced HD patients.

Midodrine Improves Chronic Hypotension in Hemodialysis Patients

The effects of midodrine on chronic hypotension in hemodialysis (HD) patients have not been well investigated. We evaluated midodrine's effect on autonomic function and hemodynamics in 12 HD patients who had chronic systolic blood pressure less than 100 mm Hg. Midodrine (5.0 mg) twice a day was given for 4 weeks. Another 12 age- and sex-matched HD patients with normotension were selected as a control group. Autonomic function tests included the heart-rate responses to the Valsalva maneuver and 30:15 ratio as well as supine and standing blood pressure (BP) and sustained hand-grip test. Hemodynamic changes included 24-hour blood pressure, cardiac output, total peripheral resistance (TPR), and plasma renin and aldosterone concentrations. Compared with the control subjects, HD patients with chronic hypotension had more severe autonomic dysfunction and significantly lower TPR. After 4 weeks of midodrine therapy, sympathetic function (orthostatic and hand-grip tests) improved in conjunction with significant increases in mean arterial pressure (MAP) (79.5 +/- 4.9 to 85.0 +/- 5.1 mm Hg, P < 0.05) and TPR (768 +/- 37 versus 1097 +/- 72 dyne/sec/cm-5, P < 0.01) despite no significant change in Valsalva ratio, 30:15 ratio, and cardiac output. MAP changes were positively correlated with TPR changes (r = 0.82, P < 0.001). Supine plasma renin activity was significantly increased. In addition, MAP during HD was also significantly increased during midodrine therapy. Midodrine improves chronic hypotension in HD patients by modulating autonomic function and its direct effects on peripheral vessels.

Autonomic nervous system function in childhood migraine.

Although the pathogenesis of migraine is controversial, autonomic nervous system (ANS) dysfunction has been reported in patients with adult migraine in recent years. The present study was planned to investigate ANS function in childhood migraine. The migraine and control groups consisted of 25 migraineur and 30 healthy children, respectively. Orthostatic test, sustained handgrip, Valsalva ratio, 30/15 ratio and heart rate responses to deep breathing were used as non-invasive ANS function tests in both groups. In the orthostatic test, systolic (SBP) and diastolic blood pressures (DBP) were higher in the upright than the supine position in the migraine group, but were higher in the supine than upright position in the control group. In the sustained handgrip test, the mean difference in SBP was higher in the migraine than the control group (P = 0.0278), but there was no significant difference in DBP between migraine and control groups (P = 0.107). The Valsalva ratio was higher in the migraine than the control group (P = 0.0002), as was the 30/15 ratio (P = 0.0108). Heart rate responses to deep breathing were not different between the migraine and control groups (P = 0.749). Our results demonstrate ANS dysfunction, with hyperactivity of both the sympathetic and parasympathetic nervous system, in children with migraine.

Reproducibility of conventional and power spectral measurements of cardiovascular sympathetic activation in normal subjects.

1. Normal subjects (n = 5; age 20-42 years; mean resting blood pressure (+/- 1 s.d.) 116 +/- 21/61 +/- 11 mmHg) underwent cardiovascular reflex testing five times each. On every occasion systolic blood pressure (SBP) responses to sustained handgrip (GRIP) and cold pressor (COLD) tests were measured and continuous non-invasive SBP and heart period (RRINT) data were analysed in the frequency domain using fast Fourier transforms. Power spectral (PS) density estimates of high frequency/total power (HF%; a measured of vagal activity), low frequency/HF ratio (LF/HF; a measure mainly of cardiovascular sympathetic activity for heart period) and low frequency/total power (LF%; a proposed measure of sympathetic activity for SBP) at rest, during and 2 min after the end of stimuli were calculated. 2. The data from the rest and recovery periods did not differ and showed that cardiovascular recovery to baseline measures following sympathetic stimulation occurred within 2 min. 3. There was a significant rise in SBP with GRIP and COLD. The LF/HF(RRINT) rose significantly with GRIP, but not with COLD. The LF%(SBP) did not change significantly with GRIP or COLD. 4. The SBP and PS analyses showed low intra-individual reproducibility of responses to reflex tests, with coefficients of variation for PS measures at rest of 25-41% and on sympathetic stimulation of up to 80%. 5. The high variability of these observations indicates that PS methods may not be suitable for the analysis of transient cardiovascular reflexes.

Cardiovascular autonomic dysfunction in multiple sclerosis is likely related to brainstem lesions

Impairment of cardiovascular autonomic reflexes has been described in multiple sclerosis (MS), and believed reflecting dysfunction of reflex pathways located within the central nervous system. A battery of cardiovascular autonomic tests were performed in 40 patients with definite MS: R-R interval variation test, deep breathing, Valsalva manoeuvre, blood pressure and heart rate responses to standing, sustained handgrip. The results were evaluated by Bayesian analysis, a pattern recognition technique. The patients had also magnetic resonance imaging (MRI) of brain and in 19 subjects of cervical spinal cord. Deep breathing test and sustained handgrip test produced most frequently abnormal results (17.5% and 40%, respectively). However, only 4 patients (10%) had two or more tests abnormal, with a very variable pattern. Evaluation by Bayesian analysis revealed 7 patients (17.5%) with definite autonomic dysfunction. A correlation was found between the confidence level obtained by Bayesian analysis, as index of autonomic function, and the Kurtzke brainstem FS score ( r = 0.43, P < 0.01). There was a significant association between presence of autonomic dysfunction and clinical ( P < 0.02) and MRI ( P < 0.005) evidence of brainstem lesions.

Autonomic function testing in patients with migraine.

Autonomic nervous system function was studied in 62 patients with migraine. The Valsalva maneuver, deep breathing test, sustained handgrip test, orthostatic test and spectral analysis of heart rate variability in the supine and standing positions were performed in a group of 62 patients of both sexes, aged 21 to 50 years, and in an age-matched control group of 45 healthy volunteers. Heart rate increases during sustained handgrip was significantly reduced in the headache group, when compared to the control group, while the results of the remaining cardiovascular tests did not significantly differ between the control and headache groups. In standing patients, the integrals of middle frequency bands of amplitude spectra were smaller in patients than in controls because the increase induced by standing was smaller in migraine patients. The results in patients with migraine with aura (21 patients) and migraine without aura (41 patients) did not differ significantly from each other. The same was true for the results of the female and male patients. It is concluded that sympathetic function is impaired in migraine patients.

Autonomic nervous system dysfunction in Parkinson's disease: relationships with age, medication, duration, and severity.

Heart rate variability at rest, during deep breathing, or standing up and with the Valsalva manoeuvre did not differ significantly between 67 patients with idiopathic Parkinson's disease (PD) and 31 healthy age matched controls. Blood pressure (BP) responses to standing up and sustained handgrip revealed diminished autonomic function in the PD group. In a preliminary analysis of the PD group older age, anti-Parkinson medication and higher Hoehn and Yahr (HY) stages were each associated with poor autonomic responsiveness. Disease duration was only related to the systolic BP fall on standing up. Multiple stepwise regression analysis showed that older age explained most of the variance of heart rate variability (up to 36%), and the only significant PD related factor was the use of medication, which explained less than 7%. The HY stage accounted for 12.7% of the variance in the standing up BP test, and the use of medication explained 10.6% of the variance of the systolic BP change in the sustained hand grip test. The unmedicated PD subgroup (n = 33), who had mild disease of short duration, showed no evidence of autonomic dysfunction. Cardiovascular autonomic dysfunction in PD is mild, mainly affects blood pressure responses, and occurs only in advanced cases.

Autonomic function testing in patients with tension-type headache.

Autonomic nervous system function was studied in 51 patients with tension-type headache. The Valsalva manoeuvre, deep breathing test, sustained handgrip test, orthostatic test and spectral analysis of heart rate variability in the supine and standing positions were performed in a group of 51 patients of both sexes aged 21 to 50 years and in an age-matched control group of 45 healthy volunteers. Diastolic blood pressure increase and particularly heart rate increase during sustained handgrip were significantly reduced in the headache group, when compared to the control group, while the results of the remaining tests did not significantly differ between the control and headache groups. No significant differences were found between the episodic (19 patients) and chronic (32 patients) tension-type headache subgroups. It is concluded that sympathetic function is impaired in tension-type headache patients.

Autonomic cardiovascular reflexes in progressive supranuclear palsy

Assessment of possible autonomic nervous system dysfunction was performed by testing cardiovascular reflexes in nine patients with progressive supranuclear palsy (PSP). The patients were significantly different from 15 control age-matched subjects because of greater blood pressure drop on standing for 1 min, diminished rise of diastolic blood pressure during the sustained handgrip test, and lack of compensatory tachycardia measured by the 30:15 ratio on standing. The latter test abnormality was caused by a slow rise to erect posture. No differences were observed in the cold pressor test, Valsalva ratio, and heart rate response to deep breathing. The differences between patients and control subjects were usually small. Autonomic nervous system involvement in patients with PSP is minor and is caused by involvement of central brain stem sympathetic nuclei or efferent fibers.

Autonomic Nervous Function in Progressive Supranuclear Palsy

Autonomic nervous function was assessed in 11 patients with progressive supranuclear palsy, 26 patients with Parkinson's disease, matched for age, medications, disease severity, and disease duration, and 19 age-matched controls. Results of both parasympathetic (heart rate response to deep breathing and Valsalva maneuver) and sympathetic (blood pressure decrease on standing and increase on sustained handgrip) tests were abnormal in both patient groups. Abnormalities in the group of patients with progressive supranuclear palsy were similar to those in the group with Parkinson's disease but were more pronounced. Autonomic dysfunction may have to be considered a feature of progressive supranuclear palsy.

Autonomic nervous system tests depend on resting heart rate and blood pressure

In order to study the effects of baseline blood pressure and heart frequency on autonomic function tests, 75 normal subjects (aged 8–96 years) were investigated. Heart rate variability was studied at rest, during deep breathing, following standing up and during a Valsalva manoeuvre. Blood pressure changes were recorded during standing up and during sustained handgrip. Responses were described as ratios and as differences to study the efficacy of both methods. Multiple regression analysis showed that significant relationships with the resting heart rate existed for ratios but not for differences. The blood pressure rise in the sustained handgrip test showed a significant relationship with resting blood pressure when the results were expressed as ratios, and the response to standing up was significantly related to the resting blood pressure regardless of the description method. As expected, relationships with age existed for all four heart rate tests regardless of the description method. The blood pressure responses were not significantly related to age. We advise that heart rate test results should be presented as differences, as this avoids the need for correction for the resting heart rate. Correction for the resting blood pressure improves the accuracy of the standing up blood pressure test. Correction for age remains necessary for heart rate tests but not for blood pressure tests.

Clinical Dysautonomia in Patients with Bronchial Asthma: Study with Seven Autonomic Function Tests

Fifty asthmatic patients and 20 healthy control subjects, carefully age- and sex-matched, were subjected to seven standardized tests to evaluate their autonomic status. Due care was taken to remove factors which could interfere with results. Of the tests concerned with the parasympathetic system, the intravenous atropine test (p>0.10) and heart rate response to standing (p>0.01) which measured the basal parasympathetic tone, did not show a significant difference. Tests requiring stimulation of the parasympathetic system, ie, deep breathing test (p<0.001), Valsalva maneuver (p<0.001), and carotid sinus massage (p<0.001) showed significantly heightened response. Postural fall of blood pressure (p>0.10) and sustained hand grip test (p>0.10), chiefly concerned with the sympathetic system, did not show a significant difference. Of the 50 asthmatic patients, nine were atopic and 41 nonatopic. When the results were compared in the two groups separately, we found that there was no alteration in the measurements except the intravenous atropine test which showed heightened response with atopic subjects (p<0.05). These results suggest that hyperresponsiveness of the parasympathetic system is an important factor in producing bronchial spasm in asthmatic patients, and atopic and nonatopic subjects do not differ much in their autonomic status. Fifty asthmatic patients and 20 healthy control subjects, carefully age- and sex-matched, were subjected to seven standardized tests to evaluate their autonomic status. Due care was taken to remove factors which could interfere with results. Of the tests concerned with the parasympathetic system, the intravenous atropine test (p>0.10) and heart rate response to standing (p>0.01) which measured the basal parasympathetic tone, did not show a significant difference. Tests requiring stimulation of the parasympathetic system, ie, deep breathing test (p<0.001), Valsalva maneuver (p<0.001), and carotid sinus massage (p<0.001) showed significantly heightened response. Postural fall of blood pressure (p>0.10) and sustained hand grip test (p>0.10), chiefly concerned with the sympathetic system, did not show a significant difference. Of the 50 asthmatic patients, nine were atopic and 41 nonatopic. When the results were compared in the two groups separately, we found that there was no alteration in the measurements except the intravenous atropine test which showed heightened response with atopic subjects (p<0.05). These results suggest that hyperresponsiveness of the parasympathetic system is an important factor in producing bronchial spasm in asthmatic patients, and atopic and nonatopic subjects do not differ much in their autonomic status.

Diabetic autonomic neuropathy: Abnormal cardiovascular reactions under general anesthesia

The influence of diabetic autonomic neuropathy upon the behavior of the circulatory system was investigated in 56 patients who had undergone ophthalmological surgery. A standardized test combination (variability in heart rate during deep breathing. Valsalva ratio, 30:15 ratio, change in blood pressure from lying to standing, sustained handgrip test) was used to study the patients' cardiovascular reflectory reactions. The patients were then divided into the following groups: Group I, non-diabetics. Group II, diabetics without autonomic neuropathy. Group III, diabetics with autonomic neuropathy. The anesthetic (induction by barbiturates and conduction by inhalation agents) and the surgical procedure (pars plana vitrectomy) were standardized and always identical. During anesthesia patients in group III experienced hypotensive reactions (systolic blood pressure below 90 mm Hg) significantly more often (72.2%) than patients in group I (25%). In order to achieve stability in blood pressure the patients of group III had to be given vasoactive drugs much more often (77.8%) than the patients of group I (12.5%) and those of group II (35.7%). We found a significant correlation between the degree of autonomic dysfunction and the largest drop in blood pressure under narcosis (r = -0.60, P less than 0.001). However, marked variability in heart rate and cardiac rhythm disorders during anesthesia were seen only in patients of groups I and II. These results prove the atypical hemodynamic behavior and especially the extreme instability in blood pressure in diabetic autonomic neuropathy under general anesthesia. Therefore we consider it to be very helpful to check the cardiovascular reflectory status of diabetics preoperatively.

Influence of cardiovascular diseases upon the results of the cardiovascular reflex tests in diabetic and nondiabetic subjects

Cardiovascular reflex tests are used to assess cardiac autonomic neuropathy in diabetes mellitus. Cardiovascular diseases (CVD) are known to alter baroreflex mechanisms. Diabetic patients are at a high risk for cardiovascular complications. In order to prove whether cardiovascular diseases reduce the diagnostic value of the cardiovascular reflex tests in diabetic autonomic neuropathy unselected groups of 274 nondiabetic and 103 diabetic patients were studied: E/I, 30/15, and Valsalva ratios, sustained handgrip test and blood pressure response to standing. Both groups were subdivided into young (less than or equal to 45 years) and older (greater than 45 years) patients and into subjects with and without CVD. In young nondiabetic patients with CVD, E/I and Valsalva ratios were significantly lower than in those without CVD. In young diabetic patients with CVD, only E/I ratios were significantly reduced compared to those without CVD. The tests reflecting sympathetic nerve function did not differ between patients with and without CVD, neither in the nondiabetic nor in the diabetic subjects. In the older nondiabetic and diabetic patients, cardiovascular reflexes were generally impaired, but did not show any difference between subjects with and without CVD. In young diabetic patients suffering from CVD, the diagnostic value of cardiovascular reflex tests is reduced as far as cardiac autonomic neuropathy is concerned. In older patients, the tests are not suitable for the diagnosis of diabetic autonomic neuropathy. More specific methods are required.