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J Smorawinski

Publications and source records attributed to J Smorawinski.

6 recordsLinked to original sources
PubMed2005

Exercise training and 3-day head down bed rest deconditioning: exercise thermoregulation.

UNLABELLED: Bed rest (BR) deconditioning causes excessive increase of exercise core body tempera-ture, while aerobic training improves exercise thermoregulation. The study was designed to determine whether 3 days of 6 degrees head-down bed rest (HDBR) affects body temperature and sweating dynamics during exercise and, if so, whether endurance training before HDBR modifies these responses. Twelve healthy men (20.7+/-0.9 yrs, VO2max: 46+/-4 ml x kg(-1) x min(-1) ) underwent HDBR twice: before and after 6 weeks of endurance training. Before and after HDBR, the subjects performed 45 min sitting cycle exercise at the same workload equal to 60% of VO2max determined before training. During exercise the VO2, HR, tympanic (Ttymp) and skin (Tsk) temperatures were recorded; sweating dynamics was assayed from a ventilated capsule on chest. Training increased VO2max by 12.1% (p<0.001). Resting Ttymp increased only after first HDBR (by 0.22 +/- 0.08 degrees C, p<0.05), while exercise equilibrium levels of Ttymp were increased (p<0.05) by 0.21 +/- 0.07 and 0.26 +/- 0.08 degrees C after first and second HDBR, respectively. Exercise mean Tsk tended to be lower after both HDBR periods. Total sweat loss and time-course of sweating responses were similar in all exercise tests. The sweating threshold related to Ttymp was elevated (p<0.05) only after first HDBR. IN CONCLUSION: six-week training regimen prevents HDBR-induced elevation of core temperature (Ttymp) at rest but not during ex-ercise. The post-HDBR increases of Ttymp without changes in sweating rate and the tendency for lower Tsk suggest an early (<3d) influence of BR on skin blood flow.

Adult↗
PubMed2003

Catecholamine responses to environmental stressors in trained and untrained men after 3-day bed rest.

INTRODUCTION: The effect of decreased physical activity with reduced gravitational stress on activity, sensitivity, and reactivity of the sympathetic nervous system (SNS) is not fully recognized. We hypothesized that the effect is most pronounced in physically active subjects. Thus, basal plasma norepinephrine [NE] and epinephrine [E], and catecholamine responses to physiological stimuli were determined after 3 d of horizontal bed rest (BR) in subjects differing in level and kind of habitual activity. METHODS: Before and after BR, 11 untrained students, 8 endurance athletes, and 10 power/strength athletes were submitted to oral glucose tolerance test (OGTT) and orthostatic stand test (OST). Another 32 men (12 untrained, 10 endurance athletes, and 10 power/strength athletes) underwent cold pressor test (CPT) and graded exercise test (GET) performed until volitional exhaustion. RESULTS: After BR, basal [NE] was decreased only in athletes (p < 0.01). Increases in both catecholamines during OGTT were diminished (p < 0.05), particularly in endurance athletes. Plasma [NE] response to standing was not affected by BR in individual groups, but it was diminished in the whole group (p < 0.05). Bed rest did not affect the increases in catecholamines induced by CPT and GET. Heart rate response to OST, and BP responses to OST, CPT, and glucose ingestion were enhanced. CONCLUSIONS: Basal sympathetic activity is diminished after 3 d of BR in physically active men. Although catecholamine responses to glucose load and standing were reduced, the general reactivity and sensitivity of SNS were not attenuated since catecholamine responses to the most (exercise) and least (CPT) powerful stimuli were unchanged.

Adult↗
PubMed1998

Comparison of changes in glucose tolerance and insulin secretion induced by three-day bed rest in sedentary subjects and endurance or strength trained athletes.

Restriction of physical activity causes exaggerated hyperinsulinemia and hyperglycemia following an oral glucose load. It is attributed to decreased sensitivity to insulin and decreased GLUT-4 transporter content in skeletal muscles. On the other hand, both endurance and strength training enhance whole body insulin sensitivity. Apart from increased insulin action in skeletal muscles, muscle hypertrophy is considered as the mechanism responsible for the training effect. Our previous study showed, that after three days of bed rest the plasma insulin response to a glucose load markedly increases both in untrained and in endurance-trained subjects; but the blood glucose (BG) response was less affected in athletes. The present investigation was designed to compare an effect of three day bed rest on BG and plasma insulin responses to oral glucose in untrained subjects, and in endurance or strength trained athletes. There are reports that the sympathetic nervous system activity is inhibited by bed-rest. Activation of this system after carbohydrate ingestion is considered an important mechanism contributing to dissipation of excess energy and prevention of postprandial fall in blood pressure. Thus, the second purpose of the present investigation was to find out whether short-term bed rest modifies changes in plasma catecholamines, heart rate and blood pressure following glucose ingestion.

Adult↗
PubMed1989

[Anti-thyroid autoantibodies in children with insulin-dependent diabetes mellitus].

The study was aimed at the assessment of frequency of occurrence of thyroid antimicrosomal and antithyreoglobuln autoantibodies in children with insulin-dependent diabetes and healthy control children. The occurrence of thyroid autoantibodies was analyzed with respect to the age and sex of children and the duration of the disease. The studied group was composed of 199 children of age between 2 and 17 years with insulin-dependent diabetes. Control group included 100 healthy children. Thyroid autoantibodies were determined by using a solid phase radioimmunoassay. Antimicrosomal antibodies were detected in 35% of diabetic children, but only in 1% of healthy children. Neither in diabetic nor in control children the occurrence of antithyreoglobulin antibodies was significant. The frequency of occurrence of antimicrosomal antibodies was not related to age of children or the duration of diabetes. The occurrence of these antibodies was significantly more frequent in girls (in 70% of cases) than in boys (30% of cases).

Adolescent↗