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AIMS: Exercise may be useful to detect patients with diabetes prone to develop persistent microalbuminuria. We studied the relationship between exercise intensity, measured as maximal oxygen consumption (VO(2)max), and microalbuminuria in patients with Type 1 diabetes mellitus patients. METHODS: We studied 10 patients, age range 10-18 years, with Type 1 diabetes who were normotensive and normoalbuminuric, with less than 10 years since diagnosis. Patients had normal renal function, without infections or clinical evidence of complications. Metabolic control was intensively adjusted in all patients. They underwent three consecutive physical exercise tests, reaching 100, 80 and 60% of the maximal cardiac frequency response. RESULTS: Eight patients had adequate to regular metabolic control. All patients had lower than predicted VO(2)max values. At 60%, only three patients showed microalbuminuria in excess of 20 µg/min, two of them had inadequate metabolic control. Post-exercise microalbuminuria exceeded normal values in nine, seven and three patients when submitted to 100, 80 and 60% of exercise intensity, respectively. CONCLUSIONS: Microalbuminuria increased with exercise intensity. Sex, body composition and VO(2)max were the main factors associated with microalbuminuria. The prognostic significance of albuminuria induced by intense exercise in these subjects with Type 1 diabetes is not yet known.

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Scintigraphy technique is considered the gold standard for gastric emptying evaluations. Lately mechanical magnetogastrography (MMG) technique has emerged as an alternative for these assessments. This study presents the determination of reference values for MMG in order to validate this novel technique in gastric emptying measurements. Both methodologies were used in young and healthy subjects provided with a solid test meal. The measurements were performed with 2 days of difference. Bland-Altman analysis of the data was performed to conclude about the feasibility of MMG as a good alternative test for gastric emptying assessments. Using MMG, an average of the gastric emptying half-time of 57.6 +/- 25.8 min was obtained, whereas the same parameter obtained by scintigraphy was 52.2 +/- 12.9 min. In conclusion, the use of MMG technique is in concordance with the results using the gold standard technique for gastric emptying measurements.

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Although it has been pointed out that the main cardiovascular risk factors in diabetic are dyslipidemias, hypertension, and cigarette smoking, very few studies have analyzed other risk factors, such as sedentarism and maximal aerobic capacity (VO2 max). The purpose of this study was to evaluate VO2 max and blood lipids (total cholesterol = TC, high density lipoproteins cholesterol = HDL; low density lipoproteins cholesterol = LDL; triglycerides = TG), in 19 diabetics subjects, 19 sedentary and 19 long distance runners. The diabetics of 5-10 years of evolution were non obese (body fat < 28%), and in regular metabolic control (Hb A1 < 12%). The athletes had more than five years of uninterrupted training. The diabetics had significantly lower VO2 max, than the other groups. The mean +/- SEM (mL/kg/min) in diabetics was 30.5 +/- 1.6 versus 41.3 +/- 2.3 in the controls and 54.2 +/- 2.5 in the athletes. There were significant group differences in TG (218 +/- 44 in diabetics vs 106 +/- 16 in controls and 94 +/- 10 mg/dL in athletes) and in HDL (27.3 +/- 4.3 in diabetes versus 34.1 +/- 4.3 and 43.9 +/- 6.3 mg/dL). These data suggest that sedentarism and low VO2 max may be important risk factors in diabetics. An aerobic program for them could perhaps change their blood lipids favorably as their VO2 max was significantly correlated with TG (r = -0.45), HDL (r = 0.52) and the TC/HDL ratio (r = -0.57).

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Influence of the autonomic nervous system on the heart rate response to active and passive orthostatism. The purposes of this study were twofold. First, to compare heart rate responses as measured by R-R interval under two conditions of orthostatic stress, i.e. a change from supine to an active free standing-up position (active orthostatism, AO), and from supine to a passive 70 head-up tilt posture (passive orthostatism, PO) second, to utilize a standard pharmacological model to study the participation of the autonomic nervous system upon heart rate responses evoked by AO. In the first part of the research, eight healthy subjects (seven men, one woman) were evaluated for AO and PO. In both occasions, subjects were supine for 5 minutes and then adopted an upright or a tilted position in 3-5 seconds and remained motionless during 5 minutes. In the second part, eight men participated twice in the pharmacological studies. In day one, they stood up for control (AOC), after IV administration of atropine sulfate (0.04 mg/kg) (AO+atro) and after IV administration of propranolol hydrochloride (0.16 mg/kg) (AO+ATRO+PROPRA). In day two, subjects repeated the control AO (AOCII) and after the administration for propranolol hydrochloride alone. In the first study, AO was characterized by a fast shortening of R-R interval, which was maximal at beat 15th (relative tachycardia), followed by a rebound lengthening of R-R interval, reaching a plateau at beat 30 (relative bradycardia), demonstrating a biphasic response. PO was characterized by a small and gradual shortening of R-R interval without the biphasic responses of AO.(ABSTRACT TRUNCATED AT 250 WORDS)

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The purpose of this study was to evaluate the effects of body postural changes (supine-upright), upon the serum concentration of cholesterol (CT), triglycerides (TG), high density lipoproteins (HDL), low density (LDL) and very low density lipoproteins (VLDL) and hemoglobin, hematocrit, and plasma proteins (to calculate delta% change in plasma y volume). Nine healthy men participated as subjects. Their age ranged from 32 +/- 3 years old, and 16 +/- 4% body fat (X +/- SD). After 10-12 hours post absorptive and appropriate rest, they performed a standard orthostatic maneuver: subjects remained supine for 30 minutes, then assumed the standing position (unsupported and with minimal movement) for additional 30 minutes. Blood samples were obtained after 30 minutes supine and at 10, 20 and 30 minutes of standing. At 10 minutes of orthostatism, CT, TG, HDL and VLDL had a significant increase as compared to supine values; these changes were associated with a reduction of 8.9% on plasma volume (PV) (p less than 0.05). After 30 minutes of orthostatism CT, TG, HDL and VLDL showed increments of 8.5%, 33.3%, 20.1% and 32% respectively, in relation to the supine values (p less than 0.05). Changes on serum lipids were associated with PV reductions until 20 minutes of orthostatism. However, there was not a significant association between these variables at 30 minutes of standing. These data indicated that the body position and the time in which blood samples are obtained significantly influence lipid and lipoprotein serum level. Therefore, in any study related to lipids, such variables should be considered and properly controlled.

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The purpose of this study was to determine the effect of a combination of aerobic exercise and hypocaloric diet on body composition, cardiovascular function and some cardiovascular risk factors in obese patients. Ten subjects, (8 women 2 men X age 30 years and 138% of ideal body weight) volunteered as participants. The program lasted 12 weeks and consisted of a hypocaloric diet (1257 kcal/day) and 3-5 days/week supervised sessions of aerobic exercise (65-90% maximal heart rate and/or 50-80% of maximal oxygen uptake). The program resulted in a significant mean decrease in body weight of 7.7 kg. for the group (P less than or equal to 0.05). Mean (+/- EE) relative body fat significantly decreased from 35.9 +/- 2 to 31.6 +/- 2%. Interestingly, the decrease in relative body fat was solely accounted for by a significant decrease in fat weight, as body free of fat remained constant. Cardiovascular function as evidenced by oxygen uptake, increased 11.3%. Resting systolic and diastolic blood pressure fell significantly from 131/90 +/- 8/9 to 115/76 +/- 2/1 mmHg. Total cholesterol significantly dropped from a mean value of 247 +/- 24 to 183 +/- 20 mg/100 ml (P less than 0.05). Triglycerides significantly decreased from 212 +/- 32 to 45 +/- 10 mg/100 ml (P less than 0.05). It was concluded that a combination of aerobic exercise and hypocaloric diet can favorably improve body composition, cardiovascular function and cardiovascular risk factors.

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Heart rate (HR), Systolic (SBP), Diastolic (DBP), and Mean Blood Pressures (MBP), were evaluated during a resting sitting and during upright moveless positions, in fifty seven highly trained runners with a maximal oxygen consumption equal or superior to 55 ml/kg. min. (VO2 max greater than or equal to 55 ml/kg . min., group I), and in fifty seven sedentary untrained men (group II). During sitting position the members of group I, had a significantly lower DBP and MBP than the members of group II. In the members of group II the assumption of upright posture did not produce significant changes in blood pressure, whereas subjects of group I showed a significantly drop in SBP, DBP and MBP. The results of this investigation indicated that in human, vigorous physical activity produce lower values of arterial blood pressure, and might be of value in the prevention of high blood pressure. On the other hand, the observed responses in group I during orthostatism, reveal a different regulation of the cardiovascular system. Changes in sympathetic and parasympathetic nervous system, venous compliance and plasma volume are designated as responsible of observed differences. This finding might also support the tendency to faintness reported by some authors in athletes.

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