Cognitive Inhibition Correlates with Exercise-Induced Hypoalgesia After Aerobic Bicycling in Pain-Free Participants

Figures & data

Figure 1 An example run of the stop-signal task, consisting of three trials. Participants’ task was to indicate the target shape (circle or a square) via button presses on go trials; on stop trials, signaled by a blue frame appearing around the target shape, no response should be given. SSD denotes stop-signal delay, please see explanation in text.

Figure 2 Scatterplot of ∆PPT after aerobic bicycling exercise at the hand and stop-signal reaction times, depicting a moderate negative correlation of (r = −0.35, 95% CI: −0.57; −0.08, p = 0.021). Note that shorter stop-signal reaction times represent better cognitive inhibition. Scatterplots for all other correlations are displayed in Figures S1–S7.

Table 1 Mean ± SD and Range for the Main Dependent Measures Directly Observed in the Stop-Signal Task, Reported Separately for Participants Included in (versus Excluded from) Subsequent Analyses

	Included Participants (N = 37)		Excluded Participants (N = 3)
	Mean ± SD	Range	Mean ± SD	Range
Probability of go omissions (no response)	0.01 ± 0.02	0 – 0.06	0.12 ± 0.14	0–0.27
Probability of choice errors on go trials	0.02 ± 0.02	0 – 0.07	0.48 ± 0.44	0.11–0.97
RT on go trials (mean)	592.67 ± 172.91	394.46–991.47	825.15 ± 253.33	544.88–1037.82
Intra-subject variability of correct go trials	103.25 ± 32.33	53.59–165.78	154.30 ± 46.65	100.44–181.73
Probability of responding on a stop trial	0.47 ± 0.06	0.34–0.58	0.38 ± 0.09	0.30–0.47
Average stop-signal delay	314.17 ± 148.29	91.41–638.28	482.55 ± 185.83	279.69–644.53
Stop-signal reaction time	261.94 ± 34.73	189.00–326.94	–	–
RT of go responses on unsuccessful stop trials	518.79 ± 149.68	355.47–882.73	680.29 ± 213.69	435.73–831.01

Notes: In line with the recommendations by Verbruggen et al⁴⁵, SSRTs were not estimated for participants with sub-optimal task performance (here: excluded participants).

Table 2 Change Scores (Δ), Displayed in Mean ± SD for PPT and TSP from Before to After Aerobic Bicycling and Isometric Knee Exercises, as Well as the Quiet Rest Control Condition, as Assessed at the Hand and the Leg with Significance and Effect Sizes (Cohen’s d) for Tests of the Difference Between Exercises and Quiet Rest

Aerobic Bicycling
	ΔPPTEIH (kPa)		ΔTSPEIH (NRS 1–10)
Hand	7.24 ± 54.60^a	p = 0.034, d = 0.52	0.35 ± 1.32^b	p = 0.453 d = 0.19
Leg	35.23 ± 75.22^b	p = 0.017, d = 0.64	−0.24 ± 1.44 ^b	p = 0.332 d = 0.27
Isometric Knee Extension
Hand	−2.83 ± 41.38^a	p = 0.136 d = 0.38	0.22 ± 1.36 ^b	p = 0.624 d = 0.10
Leg	20.68 ± 79.50^b	p = 0.137 d = 0.42	0.22 ± 1.06 ^b	p = 0.449 d = 0.10
Quiet Rest
	ΔPPTQR (kPa)		ΔPPTQR (NRS 1–10)
Hand	−21.16 ± 54.24^a	–	0.11 ± 1.10^b	–
Leg	−10.66 ± 68.17^a	–	0.11 ± 1.41^b	–

Notes: for ΔPPT, positive values indicate a decrease in pain sensitivity (ie EIH), and negative values indicate an increase in pain sensitivity (ie hyperalgesia after exercise), while the opposite is true for ΔTSP, ie positive values indicate an increase in pain sensitivity (ie hyperalgesia after exercise). P-values and Cohen’s d effect sizes refer to the test of difference between change scores in the respective exercise vs quiet rest condition (eg ∆PPT_EIH after aerobic bicycling at the hand vs ∆PPT_QR at the hand). ^aNormally distributed; t-test for dependent samples to test the difference between exercise and quiet rest. ^bNot-normally distributed; Wilcoxon-rank-sum-test for dependent samples to test the difference between exercise and quiet rest.

Table 3 Correlation Coefficients with 95% Confidence Intervals (95% CI) and p-values Between Stop-Signal Reaction Times (SSRT) and ∆PPT and ∆TSP for Each Exercise and Assessment Site. Scatterplots for Each Correlation are Displayed in Figures S1–S7

	∆PPTEIH			∆TSPEIH
	Coefficient	95% CI	p	Coefficient	95% CI	p
	Aerobic Bicycling
Hand	r = −0.35	−0.57, −0.08	0.021	rho = −0.14	−0.40, 0.14	0.397
Leg	rho = −0.10	−0.36, 0.18	0.553	rho =0.02	−0.26, 0.29	0.904
	Isometric Knee Extension
Hand	r = −0.03	−0.30, 0.25	0.884	rho = −0.09	−0.36, 0.20	0.598
Leg	rho = 0.03	−0.25, 0.30	0.857	rho = −0.06	−0.33, 0.22	0.728

Verbruggen F, Aron AR, Band GP, et al. A consensus guide to capturing the ability to inhibit actions and impulsive behaviors in the stop-signal task. Elife. 2019;8. doi:10.7554/eLife.46323

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