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Alterações da glicemia induzidas por uma corrida de endurence em jejum


Introduction: Fast happened naturally in man's phylogenesis and it was the process responsible for the development of obesity genes which allowed the storing of energy for the periods of reduction or absence of food. Fat mass, today considered as public enemy number 1 (the number of obese and overweight people is higher than the number of those who live in severe conditions of dietary constraints), may be fought with prolonged physical exercise which induces spending supplementary energy that might contribute for the decrease of ponderal excesses.

We concluded that exercising during fast promotes a superior mobilization of fat, with higher concentrations of free fat acids, glycerol and β-hydroxybutyrate (Dohm et al., 1986). However, exercise may increase hypoglycemia derived from a night of fast, inducing eventual situations of organic fallacy or strong feeling of fatigue.

Objetive: Verify the behaviour of glycemia before and after 1 hour running during a period of fast.

Materials and Methods: We analyzed the peripheral venous blood of 23 individuals, who practice running, with various levels of training and aged between 23 and 57 years old. The intensity of running was chosen for each of the individuals depending on their capacities, and they were asked to run at a level considered subjectively moderate. The individuals were asked to fast for a period of not less than 12 hours which, according to personal statements, was respected. The individuals ran an average distance of 12.064 ± 2.104 metres, with amplitude varying between 8.600 – 15.330 metres. We did descriptive statistics and the differences between the two moments according to the t-test of paired measures.

Results: The average values of glycemia before and after 1 hour running during a period of fast were 68,97±9,3 mg/dl e 74,33±31,8 mg/dl, respectively. The differences we verified were not significant (p=0,180). Nonetheless individual responses were diverse: 4 individuals changed from normoglycemia to hypoglycemia; 5 individuals were normoglycemic and they continued this way; 3 individuals were normoglycemic and they increased glycemia significatively; 6 individuals were hypoglycemic and they changed to normoglycemic; 2 individuals were hypoglycemic and they increased the blood glucose rates, however, remaining hypoglycemic; 3 individuals were hypoglycemic and they increased hypoglycemia.

Conclusion: Through this study we concluded that changes in plasma glucose rates induced by exercise during fast present a big variability and that the situations of hypoglycemia studied do not correspond to situations of physical or psychological fallacy during exercise.

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