Kinetics of catecholamines and potassium, and heart rate during exercise testing in obese subjects: Heart rate regulation in obesity during exercise

Alberto Salvadori, Paolo Fanari, Emanuela Giacomotti, Patrizia Palmulli, Giuseppe Bolla, Ilaria Tovaglieri, Livio Luzi, Erminio Longhini

Research output: Contribution to journalArticle

Abstract

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 O2 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.

Original languageEnglish
Pages (from-to)181-187
Number of pages7
JournalEuropean Journal of Nutrition
Volume42
Issue number4
DOIs
Publication statusPublished - Aug 2003

Keywords

  • Catecholamines
  • Exercise testing
  • Heart rate
  • Insulin resistance
  • Obesity
  • Potassium

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Food Science

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