The effects of different aerobic exercise intensities on serum serotonin concentrations and their association with Stroop task performance: a randomized controlled trial.
Level 2 - randomized trial
Individual randomized controlled trial in humans
PubMed 27562067 · doi:10.1007/s00421-016-3456-1
What was done
121 young adults (mean age 23.8 ± 3.6 years) were evaluated in a randomized controlled trial comprising four parallel groups: three 35-minute aerobic exercise groups at varying intensities (low intensity: 45% HRmax; moderate intensity: 65% HRmax; high intensity: 85% HRmax) and one control group. Serum serotonin (5-HT) concentrations and executive functioning (response inhibition measured by a computerized Stroop test) were assessed before and after the intervention.
What was found
A significant difference emerged between groups for serum Δ5-HT levels (p = 0.022). Post hoc tests showed significantly higher serum 5-HT in the high-intensity group compared to the control group (p = 0.013), while other group comparisons were not statistically significant. Polynomial contrast analysis demonstrated a linear association between exercise intensity and serum Δ5-HT levels (p = 0.003). For executive function, ANOVA revealed a significant difference in the Stroop reading parameter (p = 0.030) and a trend for the reverse Stroop effect (p = 0.061). Correlation analysis showed that higher 5-HT levels were associated with improved response inhibition. Exact numerical values for 5-HT levels and Stroop scores were not reported in the abstract.
Why it matters
The study shows an intensity-dependent rise in peripheral serotonin after acute aerobic exercise, providing a potential physiological correlate for exercise-induced improvements in cognitive control.
Limits
The study tested only a single acute exercise bout in healthy young adults, limiting generalizability to chronic training or older populations. Peripheral serum serotonin does not directly measure central brain serotonin levels, and the abstract omits baseline values, effect sizes, and exact group means.
Cited by
- supports High-intensity exercise significantly increases plasma serotonin levels compared to lower-intensity exercise, which correlates with improved impulse control.