The effects of different aerobic exercise intensities on serum serotonin concentrations and their association with Stroop task performance: a randomized controlled trial

Eur J Appl Physiol. 2016 Oct;116(10):2025-34. doi: 10.1007/s00421-016-3456-1. Epub 2016 Aug 25.


Purpose: 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.

Keywords: 5HT; Cognition; Executive function; Exercise; Physical activity; Serotonin.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Cognition / physiology
  • Executive Function / physiology*
  • Exercise / physiology*
  • Female
  • Humans
  • Male
  • Physical Endurance / physiology*
  • Physical Exertion / physiology*
  • Serotonin / blood*
  • Stroop Test*


  • Serotonin