title: The effects of different aerobic exercise intensities on serum serotonin concentrations and their association with Stroop task performance: a randomized controlled trial.
abstract: OBJECTIVE
  Acute exercise improves selective aspects of cognition such as executive functioning. Animal studies suggest that some effects are based on exercise-induced alterations in serotonin (5-HT) secretion. This study evaluates the impact of different aerobic exercise intensities on 5-HT serum levels as well as on executive functioning considering 5-HT as a potential mediator.
  
  
  METHODS
  121 young adults (23.8 ± 3.6 years) were examined in a randomized controlled trial including three exercise intervention (35 min) groups (low intensity, 45 % of the maximal heart rate (HRmax); moderate intensity, 65 % HRmax; high intensity, 85 % HRmax) and one control group. 5-HT levels and response inhibition (measured by a computerized Stroop test) were assessed pre- and post-intervention.
  
  
  RESULTS
  There was a significant (p = 0.022) difference between groups regarding serum Δ5-HT levels. Post hoc tests indicated significant (p = 0.013) higher 5-HT serum levels for the high-intensity group compared to the control group while other groups did not differ significantly from each other. Serum Δ5-HT levels and exercise intensity were shown to be linearly associated through polynomial contrast analysis (p = 0.003). Furthermore, ANOVA revealed a significant difference for Stroop parameter reading (p = 0.030) and a tendency for reverse Stroop effect (p = 0.061). Correlation analysis showed that augmented 5-HT levels were associated with improved results in response inhibition.
  
  
  CONCLUSIONS
  This study indicates that intensive acute exercise increases serum 5-HT levels compared to a control group. These findings might be relevant for many other related research fields in exercise science, since 5-HT receptors are expressed on many different cell types including endothelia and immune cells.
authors: Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933, Cologne, Germany. p.zimmer@dshs-koeln.de.
authors: Philipp
authors: P
authors: Zimmer
authors: Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933, Cologne, Germany.
authors: Christian
authors: C
authors: Stritt
authors: Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933, Cologne, Germany.
authors: Wilhelm
authors: W
authors: Bloch
authors: Hemostasiology and Pharmacology in the Hämostaseologicum Steglitz GmbH, Siemensstraße 27, 12247, Berlin, Germany.
authors: Frank-Peter
authors: FP
authors: Schmidt
authors: Department of Preventive and Rehabilitative Sport Medicine, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933, Cologne, Germany.
authors: Sven Thorsten
authors: ST
authors: Hübner
authors: Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933, Cologne, Germany.
authors: Stephan
authors: S
authors: Binnebößel
authors: Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933, Cologne, Germany.
authors: Alexander
authors: A
authors: Schenk
authors: Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933, Cologne, Germany.
authors: Max
authors: M
authors: Oberste
mesh_terms: D000328:Adult; D003071:Cognition / Q000502:physiology; D056344:Executive Function / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010807:Physical Endurance / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D012701:Serotonin / Q000097:blood*; D057190:Stroop Test
chemical_list: D012701:Serotonin
keywords: 5HT; Cognition; Executive function; Exercise; Physical activity; Serotonin