Heart disorders can capture both overweight, obese

A new study has suggested that overweight and obese adolescents have similar risks of developing heart disorders. The study published in the journal 'Cardiology in the Young' is the results of cardiovascular fitness tests with volunteers aged 10-17 were similar in both groups.

"Until recently, overweight in adolescence wasn't considered as important risk as obesity for the development of the cardiovascular disease. We found the risks to be similar in both cases," said Vitor Engracia Valenti, the principal investigator for the project. The researchers divided 40 adolescents aged between 10 and 17 into two groups, each with ten boys and ten girls: an overweight group with BMI-for-age Z-scores of +1 or +2 and an obese group with Z-scores above +2.

Z-scores indicate the number of standard deviations below or above the population mean. The participants performed a moderate exercise protocol, which involved walking on a treadmill at a slope of 0 per cent and required 70 per cent of the maximum estimated heart rate for this age group.

Heart rate variability was measured before and after the exercise session to assess the speed of autonomic cardiac function recovery. Prolonged autonomic nervous system imbalances after physical exertion have been shown to increase the risk of an acute event and of future cardiovascular disease. During the first few seconds of an exercise session, the parasympathetic nervous system decelerates cardiac function. One of the two main divisions of the autonomic nervous system, this system conserves energy by slowing the heart rate and relaxing the body in other ways. After 50-60 seconds, the sympathetic nervous system kicks in, stimulating activity such as increased heart rate via adrenalin release, which prepares the body to react to a stressful situation.

The researchers found no significant difference in heart rate variability between overweight and obese adolescents or between girls and boys. "The mean autonomic nervous system variables were practically identical for both groups regardless of sex," Valenti said.

"These findings suggest that overweight adolescents have the same predisposition or vulnerability as that of obese adolescents to cardiovascular diseases such as hypertension and heart failure, as well as to metabolic disorders such as diabetes, dyslipidemia, and high levels of triglycerides and LDL cholesterol," Valenti added. 

(With inputs from agencies.)