BACKGROUND: Obesity is characterised by a marked insulin resistance which involves an abnormal regulation of K(+) uptake and metabolism. Less is known about the effect of physical exercise on K(+) kinetics. AIM OF THE STUDY: To assess plasma catecholamines and potassium levels and their relationship with cardiac activity during a physical effort up to exhaustion in young obese subjects. METHODS: Blood samples for epinephrine (E), norepinephrine (NE), potassium (K+) and heart rate (HR) were collected at the end of every step during a progressive cycloergometric test up to exhaustion in twelve obese subjects (6 males, aged 26+/-2, BMI 39.9+/-1) and twelve normal subjects (6 males, aged 28.2+/-2, BMI 22+/-1). In every subject anaerobic threshold (AT) was detected. RESULTS: In obese subjects plasma catecholamines rose faster but had a lower peak in correspondence of maximal work-loads, with respect to controls. Catecholamines had a linear correlation in the obese group and a quadratic one in the control group when plotted vs O(2) consumption. The increase of plasma potassium was less in obesity than in control. CONCLUSIONS: During physical exercise K(+) and catecholamines kinetics differ significantly in obese subjects vs normals and they may justify a less prompt cardiac response at the higher work-loads and a lower work capacity. The present data can be interpreted in the light of the insulin resistance syndrome of obesity, which causes an abnormal regulation of the Na-KATPase and of K(+) channels during physical exercise. The results of the present study may be relevant to nutritionists when suggesting physical exercise to obese subjects.
BACKGROUND:Obesity is characterised by a marked insulin resistance which involves an abnormal regulation of K(+) uptake and metabolism. Less is known about the effect of physical exercise on K(+) kinetics. AIM OF THE STUDY: To assess plasma catecholamines and potassium levels and their relationship with cardiac activity during a physical effort up to exhaustion in young obese subjects. METHODS: Blood samples for epinephrine (E), norepinephrine (NE), potassium (K+) and heart rate (HR) were collected at the end of every step during a progressive cycloergometric test up to exhaustion in twelve obese subjects (6 males, aged 26+/-2, BMI 39.9+/-1) and twelve normal subjects (6 males, aged 28.2+/-2, BMI 22+/-1). In every subject anaerobic threshold (AT) was detected. RESULTS: In obese subjects plasma catecholamines rose faster but had a lower peak in correspondence of maximal work-loads, with respect to controls. Catecholamines had a linear correlation in the obese group and a quadratic one in the control group when plotted vs O(2) consumption. The increase of plasma potassium was less in obesity than in control. CONCLUSIONS: During physical exercise K(+) and catecholamines kinetics differ significantly in obese subjects vs normals and they may justify a less prompt cardiac response at the higher work-loads and a lower work capacity. The present data can be interpreted in the light of the insulin resistance syndrome of obesity, which causes an abnormal regulation of the Na-KATPase and of K(+) channels during physical exercise. The results of the present study may be relevant to nutritionists when suggesting physical exercise to obese subjects.
Authors: Anne-Caroline Norman; Bart Drinkard; Jennifer R McDuffie; Samareh Ghorbani; Lisa B Yanoff; Jack A Yanovski Journal: Pediatrics Date: 2005-06 Impact factor: 7.124
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Authors: Fotini Tsofliou; Yannis P Pitsiladis; Jose Lara; Marios Hadjicharalambous; Ian A Macdonald; Mike A Wallace; Mike E J Lean Journal: Nutr Health Date: 2020-07-30