Cardiovascular responses and postexercise hypotension after arm cycling exercise in subjects with spinal cord injury

OBJECTIVE: To examine postexercise hypotension and contributing factors in subjects with spinal cord injury (SCI). DESIGN: Prospective clinical research study. SETTING: Rehabilitation center. PARTICIPANTS: Subjects with chronic cervical-level (n=19) and thoracic-level (n=8) SCI. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Subjects underwent graded arm-cycling with electrocardiogram and oxygen uptake monitoring to exhaustion. Heart rates and blood pressures were measured before and after exercising. Injury to motor and sensory pathways was determined by American Spinal Injury Association grade, and to autonomic pathways by sympathetic skin responses (SSRs) (n=16). RESULTS: Resting blood pressures and heart rates were lower in cervical than thoracic SCI (mean arterial pressure [MAP]: cervical, 76.6+/-2 mmHg; thoracic, 93.5+/-3 mmHg; P<.001). Following exercise, heart rate responses were greater in thoracic than cervical SCI; MAP increased in thoracic SCI (8.4+/-5 mmHg) and markedly decreased in cervical SCI (-9.3+/-2 mmHg) (P<.001). No subject had significant electrocardiographic abnormalities at rest or during exercise. There were correlations between SSR and heart rate and blood pressure responses to exercise; the correlation between the SSR and blood pressure response was due to an interaction between the heart rate and blood pressure responses. CONCLUSIONS: Abnormal cardiovascular responses to exercise and transient postexercise hypotension were common in cervical, but not thoracic SCI. This may be partly related to loss of descending sympathetic nervous control of the heart and vasculature following high SCI.     

Hemodynamic and metabolic responses of the exercising lower limb of humans

This study was performed to determine the hemodynamic and metabolic responses of the human lower limb during exercise. Blood flow to the lower extremity was measured and sampled for lactate, catecholamines, and oxygen content in 12 normal men at rest, at all stages of bicycle ergometry, and during the postexercise recovery period. Whole body oxygen consumption and cardiac output were recorded throughout the experiment. Limb blood flow increased in a near-linear manner with both whole body and limb oxygen consumption. Although cardiac output rose with increasing whole body oxygen consumption, the increment in cardiac output diminished between submaximal and maximal levels of exercise resulting in a curvilinear relationship between blood flow to the exercising limb and cardiac output; this indicates that a major redistribution of cardiac output to the exercising lower extremity occurs, particularly at maximal levels of exercise. Covariance analysis suggested that limb oxygen consumption was the primary determinant of limb blood flow and limb vascular resistance during exercise. Arterial and venous lactate and catecholamine concentrations, obtained from the exercising lower extremity, could not be implicated as factors having a major influence on blood flow to that limb. The rate of lactate efflux from the limb during and after exercise, however, was directly related to limb blood flow.     

The 10-s maximal sprint: a novel approach to counter an exercise-mediated fall in glycemia in individuals with type 1 diabetes

OBJECTIVE: To investigate whether a short maximal sprint can provide another means to counter the rapid fall in glycemia associated with moderate-intensity exercise in individuals with type 1 diabetes and therefore decrease the risk of early postexercise hypoglycemia. RESEARCH DESIGN AND METHODS: In the study, seven male subjects with type 1 diabetes injected their normal insulin dose and ate their usual breakfast. When their postprandial glycemia fell to approximately 11 mmol/l, they pedaled at 40% Vo(2peak) for 20 min on a cycle ergometer then immediately engaged in a maximal 10-s cycling sprint (sprint trial) or rested (control trial); the sprint and rest trials were administered in a counterbalanced order. RESULTS: Moderate-intensity exercise resulted in a significant fall (P < 0.05) in glycemia in both trials (means +/- SE: 3.6 +/- 0.5 vs. 3.1 +/- 0.5 mmol/l for sprint and control, respectively). The subsequent short cycling sprint opposed a further fall in glycemia for 120 min, whereas in the absence of a sprint, glycemia decreased further (3.6 +/- 1.22 mmol/l; P < 0.05) after exercise. The stabilization of glycemia in the sprint trial was associated with elevated levels of catecholamines, growth hormone, and cortisol. In contrast, these hormones remained at stable or near-stable levels in the control trial. Changes in insulin and free fatty acid levels were similar in the sprint and control trials. CONCLUSIONS: These results suggest that after moderate-intensity exercise, it is preferable for young individuals with insulin-treated, complication-free type 1 diabetes to engage in a 10-s maximal sprint to acutely oppose a further fall in glycemia than to only rest. The addition of the sprint after moderate-intensity exercise provides another means to reduce the risk of hypoglycemia in active individuals with type 1 diabetes.     

The decline in blood glucose levels is less with intermittent high-intensity compared with moderate exercise in individuals with type 1 diabetes

OBJECTIVE: To compare the response of blood glucose levels to intermittent high-intensity exercise (IHE) and moderate-intensity exercise (MOD) in individuals with type 1 diabetes. RESEARCH DESIGN AND METHODS: Seven healthy individuals with type 1 diabetes were tested on two separate occasions, during which either a 30-min MOD or IHE protocol was performed. MOD consisted of continuous exercise at 40% Vo(2peak), while the IHE protocol involved a combination of continuous exercise at 40% Vo(2peak) interspersed with 4-s sprints performed every 2 min to simulate the activity patterns of team sports. RESULTS: Both exercise protocols resulted in a decline in blood glucose levels. However, the decline was greater with MOD (-4.4 +/- 1.2 mmol/l) compared with IHE (-2.9 +/- 0.8 mmol/l; P < 0.05), despite the performance of a greater amount of total work with IHE (P < 0.05). During 60 min of recovery from exercise, glucose levels remained higher in IHE compared with MOD (P < 0.05). Furthermore, glucose levels remained stable during recovery from IHE, while they continued to decrease after MOD (P < 0.05). The stabilization of blood glucose levels with IHE was associated with elevated levels of lactate, catecholamines, and growth hormone during early recovery from exercise (P < 0.05). There were no differences in free insulin, glucagon, cortisol, or free fatty acids between MOD and IHE. CONCLUSIONS: The decline in blood glucose levels is less with IHE compared with MOD during both exercise and recovery in individuals with type 1 diabetes.     

Chronotropic incompetence to exercise separates low body weight from established anorexia nervosa

Chronotropic incompetence (CI), characterized by an attenuated heart rate (HR) response to exercise could participate to the limitation of exercise capacity in anorexia nervosa (AN). Therefore, we evaluated the role of cardiac sympathetic responsiveness in AN patients. In addition, the ambulatory value of autonomic control using spectral analysis of heart rate variability (HRV) was determined and correlated to maximal exercise performance. Twenty-two patients hospitalized for weight loss and suspicion of AN were included in the study. All performed a symptom-limited exercise test with measurement of gas exchange for chronotropic response to exercise evaluation. Holter ECG recordings allowed daytime and night-time spectral domain HRV analysis in order to evaluate the alteration of sympathetic control of HR in free-living conditions. CI defined as a failure to achieve 80% of heart rate reserve (%HRR) was observed in 13 (59%) patients (CI+). This group presented a higher body mass deficit than the group without CI (CI-; -35.1 +/- 8.7% versus -26.1 +/- 10.7%; P<0.05). Obviously, patients with a lower body mass index (BMI < 16 kg m(-2), n = 14) revealed a more severe limitation to maximal exercise with a lower peak HR, a lower peak Vo(2), and a lower maximal O(2) pulse (P<0.05). BMI was significantly correlated to peak Vo(2), maximal HR, and %HRR achieved at peak exercise. Daytime HRV parameters reflecting the sympathetic autonomic equilibrium (LF nu, LF/HF ratio) were significantly lower in CI+ patients. Blunted sympathetic response to maximal exercise is frequent and correlated to weight deficit. The present data suggest a major autonomic derangement in AN characterized by a cardiac sympathetic withdrawal.     

Effects of graduated compression stockings on blood lactate following an exhaustive bout of exercise

To determine the effects of wearing graduated compression stockings (GCS) on the exercise response, twelve high fit males served as subjects in a series of two experiments. The first experiment consisted of six subjects performing two tests of maximal oxygen consumption (VO2 max) on a treadmill with and without GCS. The second experiment consisted of six subjects performing three separate three minute tests on a bicycle ergometer at 110% of their VO2 max. The experimental conditions for the three tests were: GCS worn during the test and recovery (GCS), GCS worn only during the test (GCS-O/O) and no stockings worn during either the test or recovery (NO-GCS). Oxygen consumption (VO2) was measured at rest, throughout the duration of all tests and during recovery in both experiments. Blood samples were obtained at rest and at 5, 15, 30, 45 and 60 minutes post exercise in the first experiment and at rest and at 5, 15 and 30 minutes post exercise in the second experiment for the determination of lactate and hematocrit. The use of GCS in the first experiment resulted in no significant difference in VO2 max, recovery VO2 or plasma volume shifts. Lactate values were lower throughout the duration of the recovery period with the 15 minute values being significantly different with the use of GCS. Significant differences in post exercise blood lactate values were found in the second experiment. The GCS trial resulted in significantly less lactate when compared to the GCS-O/O and the NO-GCS trials. There was no significant difference in post exercise lactate values between the NO-GCS and the GCS-O/O trials. Plasma volume changes were not significantly different among trials. Results of both experiments showed recovery lactate values to be lower with the use of GCS. These lower values are not ascribable to plasma volume shifts but rather appear to be due to an inverse gradient created by the GCS resulting in the lactate being retained in the muscular bed.     

Cardiac vagal activity following three intensities of exercise in humans

Cardioprotective benefits of exercising at vigorous intensities are known, but reservations remain in prescribing such activity to the untrained population, due to a perceived risk of cardiac events. Few studies have investigated the recovery of the autonomic nervous system (ANS) after a single exercise bout, especially following vigorous exercise in healthy, young but untrained individuals. In this study, the recovery of the ANS, in particular indices of vagal activity were measured postexercise, at three intensities similar to current international recommendations for health. Thirteen individuals (six females, 22·2 ± 3·1 years) performed three 20‐min constant load tests lying supine on a modified bicycle ergometer at the following intensities: moderate (2 mmol l^?1 blood lactate concentration, BLC); hard (3 mmol l^?1BLC); and vigorous (4 mmol l^?1BLC) as derived from a maximal test. ECG data were collected during 5‐min epochs at baseline then at: 5, 15, 30, 45 and 65‐min postexercise. Heart rate variability (HRV) analysis was performed to obtain R–R interval, standard time [root mean square of successive differences (RMSSD)] and frequency measures [natural logarithm of high (lnHF) and low frequency (lnHF)]. RMSSD, lnHF, lnLF and total power were reduced 5‐min postexercise following all three intensities (P<0·01). Decreases persisted up to 15‐min postexercise following hard and vigorous exercise only (P<0·01). In untrained young adults, parasympathetic reactivation is reduced up to 5‐min postexercise regardless of intensity, returning to baseline by 30 min even after vigorous exercise. In this population, the benefits of exercise outweigh any risks of cardiac events that may be evoked by a reduction in the influence of vagal activity.     

Reproducibility of noninvasive cardiac output during arm exercise in spinal cord injury

The carbon dioxide (CO(2)) rebreathing method is a noninvasive technique to estimate cardiac output during exercise, but few data are available on the validity and reliability of this measure in individuals with spinal cord injury (SCI). Sixteen male subjects with SCI (mean age 45 +/- 9, seven paraplegic and nine tetraplegic) underwent three submaximal steady state arm ergometer exercise tests. We estimated cardiac output using the exponential CO(2) rebreathing technique at an individualized exercise intensity approximating 50% of peak oxygen uptake. Mean values for the cardiac output measurements were 13.0 +/- 2.4, 13.3 +/- 2.0, and 13.4 +/- 1.7 L/min; the difference among the trials was not significant (p = 0.54). The typical error was 1.80 +/- 0.85 L/min, the limits of agreement were 11.3 to 15.3 L/min, the coefficient of variation was 5.4% +/- 3.4%, and the intraclass correlation coefficient was 0.85 (95% confidence interval = 0.70-0.94). The test-to-test variation in estimated cardiac output during arm ergometry in individuals with SCI is similar to that observed in studies that used this technique in ambulatory persons. The 5% relative variation between tests suggests that the CO(2) rebreathing technique for estimating cardiac output can be performed in SCI individuals with acceptable reproducibility.     

Reliability of graded exercise testing after traumatic brain injury: submaximal and peak responses

OBJECTIVE: To assess the reliability of the submaximal and peak responses to a treadmill graded exercise test in individuals recovering from traumatic brain injury. DESIGN: A total of 15 individuals (11 men, 4 women; 28.5 +/- 9.2 yrs) with moderate to severe traumatic brain injury admitted into a postacute residential treatment center 10 +/- 7 mos after injury performed two treadmill graded exercise tests separated by 4-8 days. Heart rate, oxygen consumption (in milliliters per minute per kilogram), minute ventilation (in liters per minute), and respiratory exchange ratio (carbon dioxide output/oxygen consumption) were continuously monitored at 1-min intervals. Submaximal and peak values were analyzed for absolute level of agreement using the intraclass correlation coefficient. RESULTS: The submaximal intraclass correlation coefficient values for all variables between minutes 3 and 7 ranged from 0.80 to 0.93. Submaximal intraclass correlation coefficients before and in the subsequent minutes were less than optimal for heart rate and minute ventilation. Lower intensity workloads elicited slightly better agreement than higher intensity workloads. The peak response intraclass correlation coefficients ranged from 0.77 (heart rate) to 0.92 (oxygen consumption). CONCLUSION: Despite the presence of other co-morbidities, subjects recovering from traumatic brain injury provided consistent individual responses, allowing for reliable assessments of cardiorespiratory conditioning programs. Assessments of ambulatory efficiency, endurance, and aerobic fitness adaptations as a result of treatment for persons with traumatic brain injury should include analyses of submaximal responses to graded exercise.     

Effects of chronic dobutamine administration on the response to acute exercise in dogs

Summary. The effects of chronic dobutamine administration on haemodynamic and metabolic responses to submaximal and maximal exercise were studied in dogs. Dobutamine was infused at a rate of 40 μg/kg min^-1, 2 h day^-1, 5 days week^-1 for a period of 6 weeks. Acute infusion of dobutamine for 1 h increased heart rate by 73 ± 30 beats min^-1 and cardiac output by 143 ± 141 ml/min kg^-1, reduced mean arterial blood pressure by 12 ± 10 mmHg and arterial-venous O₂ difference by 1.5 ± 1 vol%. Maximal oxygen consumption, heart rate, stroke volume, cardiac output and arterial-venous O₂ difference were unchanged after 6 weeks of treatment. Reductions in heart rate at rest and during submaximal exercise following chronic dobutamine treatment were small and significant only at the lowest exercise level studied. Mixed venous lactate concentrations measured at rest, during submaximal and maximal exercise and at 2 min of recovery were not different after dobutamine treatment. Chronic dobutamine infusion did not change the citrate synthase activity in the lateral gastrocnemius muscle. These results suggest that chronic dobutamine therapy in healthy dogs does not produce aerobic training responses.     

Arterial and venous measurement in resting forearm of metabolic indicators during rest and leg exercise

Summary. We compared the levels of various metabolic indicators in arterial and venous forearm blood during maximal treadmill leg exercise, and the subsequent 9 min in nine volunteers aged 31–56 years. At maximal exercise plasma lactate was 13·2 ± 3·1 mmol 1^-1 arterially, while venous was 41% lower, but increased more than arterial after exercise. There was a linear relationship between arterial and venous samples during and after exercise, but not at baseline. Plasma pyruvate increased on the arterial side from 49 ± 8 to 172 ± 30 μmol 1^-1 at maximal exercise, maximal venous was 21% lower. Free fatty acids were not different at rest, but decreased during exercise by 52 and 38% on the arterial and venous side. There was no relationship between arterial and venous levels. Changes in these three variables occurred significantly earlier on the arterial side. Arterial cyclic AMP rose from 97·3 ± 28·4 to 262·7 ± 67·5 nmol 1^-1 from rest to exercise, and was linearly inversely related to the decrease in free fatty acids. The mean venous pH was lower than arterial at rest, but was the same as arterial at maximal exercise and after. Thus, venous plasma lactate and pyruvate, but not free fatty acids, are linearly related to arterial measurements during maximal exercise, while pH is identical. Non-working muscle modifies exercise-induced changes, and therefore venous and arterial forearm blood sampling give more information than either alone.     

The measurement properties of fitness measures and health status for persons with spinal cord injuries

OBJECTIVE: To assess the measurement properties of measures used to evaluate fitness and health status in the spinal cord injury (SCI) population. DESIGN: Inception cohort assessed during standardized exercise protocols at admission, discharge, and 8-week follow-up from a SCI rehabilitation program. SETTING: Urban tertiary care hospital. PATIENTS: One hundred two patients with SCI. RESULTS: Measures at higher levels of physical exertion generally showed higher stability between test and retest. Resting measures, blood lactates, and respiratory exchange ratios were not stable. Heart rate, blood pressure, lactate levels, ventilation rates, and activities of daily living measures did not reflect the construct of aerobic fitness. The use of ratings of perceived exertion to predict heart rate was found to be inaccurate in the SCI population. CONCLUSION: Power output and VO2 at maximal workload, and ratings of perceived exertion at a standard workload demonstrated stability and sensitivity to therapeutic change, indicating acceptable measurement properties for the assessment of aerobic fitness in SCI patients. Some other commonly used measures can be used with less confidence.     

Biochemical changes in relation to a maximal exercise test in patients with fibromyalgia

Summary. Patients with fibromyalgia often complain of fatigue and pain during exercise and of worsening of pain days after exercise. The aim of the study described here was to determine if abnormal changes in potassium or lactate could be observed during an exercise test in fibromyalgia. Whether an abnormal incline in plasma creatine kinase or myoglobin could be observed days after the test was studied also. Fifteen female fibromyalgia patients and 15 age- and sex-matched controls performed a stepwise incremental maximal bicycle-ergometer test. Blood samples were collected from a catheter in a cubital vein. The changes in heart rate, potassium levels, and haematocrit during the exercise test were similar in the two groups. The maximal obtained lactate concentration was 4-2 mmol 1^-1 (3–5-5-6) in the patients as compared to 4–9 mmol l^-1 (3–9-5-9) in the controls (NS). The estimated anaerobic threshold of 2 mmol 1^-1 was reached at a heart rate of 124 min^-1 in the patients with fibromyalgia as compared to 140 min^-1 in the controls (P= 0–02). In relation to workload, the patients scored higher on a Borg scale for perceived exertion during exercise, but if the Borg score was related to lactate no significant difference was found. The patients reported 86% and 79% of maximal pain in the thighs on the visual analogue scale 1 and 2 days after the test, but the creatine kinase and myoglobin concentrations were not increased.,     

Mechanisms of impaired exercise capacity in short duration experimental hyperthyroidism.

To investigate the mechanism of reduced exercise tolerance in hyperthyroidism, we characterized cardiovascular function and determinants of skeletal muscle metabolism in 18 healthy subjects aged 26 +/- 1 yr (mean +/- SE) before and after 2 wk of daily ingestion of 100 micrograms of triiodothyronine (T3). Resting oxygen uptake, heart rate, and cardiac output increased and heart rate and cardiac output at the same submaximal exercise intensity were higher in the hyperthyroid state (P less than 0.05). However, maximal oxygen uptake decreased after T3 administration (3.08 +/- 0.17 vs. 2.94 +/- 0.19 l/min; P less than 0.001) despite increased heart rate and cardiac output at maximal exercise (P less than 0.05). Plasma lactic acid concentration at an equivalent submaximal exercise intensity was elevated 25% (P less than 0.01) and the arteriovenous oxygen difference at maximal effort was reduced (P less than 0.05) in the hyperthyroid state. These effects were associated with a 21-37% decline in activities of oxidative (P less than 0.001) and glycolytic (P less than 0.05) enzymes in skeletal muscle and a 15% decrease in type IIA muscle fiber cross-sectional area (P less than 0.05). Lean body mass was reduced (P less than 0.001) and the rates of whole body leucine oxidation and protein breakdown were enhanced (P less than 0.05). Thus, exercise tolerance is impaired in short duration hyperthyroidism because of decreased skeletal muscle mass and oxidative capacity related to accelerated protein catabolism but cardiac pump function is not reduced.     

Static exercise-induced increase in blood pressure in individuals with cervical spinal cord injury

OBJECTIVE: To compare the pressor response to static exercise in subjects with cervical spinal cord injury (SCI) at the C6 to C8 level with that in able-bodied control subjects. In these SCI subjects, the descending supraspinal sympathetic neurons and afferent pathways from the contracting muscles to peripheral vessels via the medullary cardiovascular center are damaged. DESIGN: Mean arterial blood pressure, heart rate, and plasma concentrations of norepinephrine, epinephrine, renin activity, vasopressin, aldosterone, and human atrial natriuretic peptide were measured during a 2-minute period of sustained contraction of elbow flexor group muscle in 7 SCI subjects and 7 age-matched able-bodied control subjects. RESULTS: Static exercise resulted in a significant increase in mean blood pressure (p<.05) in both SCI subjects (pre-exercise. 74.7+/-2.2 mm Hg; static exercise, 81.9+/-4.1 mm Hg) and control subjects (pre-exercise, 101.0+/-4.2 mm Hg; static exercise, 117.0+/-4.9 mm Hg). In SCI subjects, there was no change in heart rate during exercise, whereas in control subjects heart rate increased during exercise (p<.05) (pre-exercise, 8.7+/-3.8 beats/min: static exercise, 76.0+/-3.1 beats/min). There were no significant changes in the hormone levels in the SCI subjects throughout the experiment. CONCLUSION: The significant increase in mean blood pressure observed in the present study indicates the presence of peripheral control from muscle receptors and evoked pressor response during static exercise in SCI subjects.     

Exertional symptoms and exercise capacity in individuals with brain injury

PURPOSE: To examine factors affecting cycling exercise performance in individuals with acquired brain injury. METHODS: Thirty individuals with acquired brain injury and 18 sedentary controls (SC) participated. Heart rate, bicycle power output and rating of perceived exertional (RPE) were recorded, throughout incremental cycle ergometer exercise. The SC group and 18 moderately impaired individuals from the ABI group performed a 25-W (B25) protocol. The remaining 12 individuals performed a 10-W protocol (B10). RESULTS: The B10 group terminated exercise at the lowest RPE, percentage age predicted maximal heart rate (% APMHR) and bicycle power output, followed by the B25 and then the SC group (RPE: Kruskal - Wallis test P < 0.001, %APMHR and bicycle power output: one-way ANOVA P < 0.01). RPE was correlated with %APMHR and percentage of peak bicycle output (B10 group: R2 0.1 to 0.67; B25 group: 0.69 - 0.83; SC group: 0.76 - 0.91). There was no difference in RPE at the same relative work intensity between the B25 and the sedentary control group (P > 0.05). Forward regression analysis revealed fatigue levels were predictive of %APMHR at test termination (beta = -0.411, P < 0.05) and quadriceps strength was predictive of peak bicycle power output (beta = 0.612, P < 0.05). CONCLUSIONS: Individuals with brain injury terminated exercise at lower exercise intensities but rated exertion no differently from healthy individuals. General fatigue levels predicted %APMHR and quadriceps strength predicted peak bicycle power output.     

Decreased exercise heart rate and blood pressure response in diabetic subjects with cardiac autonomic neuropathy

Abnormal hemodynamic responses to exercise have been observed in diabetic subjects, but the pathogenesis and significance remain uncertain. We used maximal treadmill exercise to study 32 subjects with long-term insulin-dependent diabetes without clinical evidence of cardiac disease. Two of the 32 had occult ischemic heart disease revealed by stress electrocardiography and myocardial-perfusion scintigraphy and were excluded from subsequent analysis. In the remaining 30 subjects, we compared the responses to exercise of the 17 subjects with cardiac autonomic neuropathy diagnosed by noninvasive maneuvers (group 1) with the 13 without (group 2). At rest, the pressure-rate product (PRP) was higher in group 1 (114.0 +/- 5.7 vs. 95.9 +/- 5.3, P less than .05). With maximal exercise the increase in heart rate (44.6 +/- 4.8 vs. 79.0 +/- 5.4 beats/min, P less than .001), systolic blood pressure (36.8 +/- 5.9 vs. 55.0 +/- 5.8 mmHg, P = .02), and the PRP (102.0 +/- 7.3 vs. 182.0 +/- 8.2, P less than .001) were all lower in group 1 than in group 2, despite similar total treadmill times (631 +/- 47 vs. 587 +/- 40 s, P greater than .1). At each stage of exercise, the increase in heart rate and systolic blood pressure was lower in group 1 patients. The severity of cardiac autonomic neuropathy correlated inversely with the maximal increase in heart rate (r = -.68, P less than .001) and the PRP (r = -.58, P less than .005). Age, duration of diabetes, and the presence and severity of microvascular disease did not correlate with any of the hemodynamic parameters.(ABSTRACT TRUNCATED AT 250 WORDS)