Investigating the Inverted-U Relationship Between Cognitive Performance and Plasma Epinephrine

Not Applicable

• Conditions: Healthy Young Adults
• Interventions: Behavioral: Resistance exercise

• Registration Number: NCT05407259
• Lead Sponsor: National Taiwan Normal University

Brief Summary

Abstract Although acute resistance exercise has been suggested to enhance inhibitory control, a critical component of executive function, the mechanism by which acute exercise influences inhibitory control is unclear and there are methodological limitations in previous empirical studies. According to the locus coeruleus-norepinephrine (LC-NE) theory, the activity of the LC, the major releaser of NE in the brain, regulates inhibitory control. Because there is reciprocal communication between circulating epinephrine and the LC. Plasma epinephrine is chosen as the index of LC-NE activity. However, only one study in acute exercise-inhibitory control measured the plasma epinephrine. Therefore, this registered report aims to extend its findings by a four-arm crossover randomized controlled design with three different intensities, using free-weight, multiple-joint, and structural resistance exercises. Moreover, most studies showed some methodological limitations such as failing to report the process of randomization, implementing a familiarization of resistance exercise before the maximal strength test, and publishing the protocol. Without a transparent report on how the participants were allocated, the results were at risk of bias. Without a familiarization of resistance exercise, the maximal muscle strength was likely to be underestimated. Without publishing the protocol before data collection, these findings were threatened by undetected researchers' degrees of freedom such as HARKing (hypothesizing after the results are known), cherry picking, and p-hacking. This registered report will address the limitations of previous studies by incorporating cognitive and resistance exercise familiarization, transparently reporting the randomization process, and submitting it as a registered report.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2022-05-26
• Status Verified: 2022-06
• Study Start: 2022-06-01
• Study First Submitted QC: 2022-06-01
• Study First Posted: 2022-06-07
• Last Update Submitted: 2022-06-07
• Last Update Posted: 2022-06-09
• Primary Completion: 2023-09-30
• Study Completion: 2023-12-31

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: Male
• Target Recruitment: 40

Inclusion Criteria

1. healthy young male aged 18-40 years;
2. recreational resistance-trained (≥ 1 time/week for the previous 6 months);
3. free from cardiovascular, cerebrovascular, and neurological disorders and other chronic diseases;
4. free from any medical condition listed on the 2014 update of the Physical Activity Readiness Questionnaire (PAR-Q+);
5. non-smoker; and
6. normal or corrected-to-normal vision.

Exclusion Criteria

1. athlete trained in a competitive sports team or engaging in exercise for more than 20 hours/week;
2. unable to perform any of the intervention exercises (barbell squat, press, and deadlift); or
3. color blind

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Low-intensity barbell resistance exercise	Resistance exercise	Exercise: Barbell squat, barbell press, and barbell deadlift Number of sets: 3 Number of repetitions: 5 Intensity: 65% 1RM Training method: Circuit training (Squat set 1 ➔ Press set 1 ➔ Deadlift set 1 ➔ Squat set 2 ➔ Press set 2 ➔ Deadlift set 2 ➔ Squat set 3 ➔ Press set 3 ➔ Deadlift set 3) Rest interval between exercises and sets: \~3 minutes (Warm-up: 1 set of 5 repetitions for each exercise at 50% 1RM)
Moderate-intensity barbell resistance exercise	Resistance exercise	Exercise: Barbell squat, barbell press, and barbell deadlift Number of sets: 3 Number of repetitions: 5 Intensity: 72% 1RM Training method: Circuit training (Squat set 1 ➔ Press set 1 ➔ Deadlift set 1 ➔ Squat set 2 ➔ Press set 2 ➔ Deadlift set 2 ➔ Squat set 3 ➔ Press set 3 ➔ Deadlift set 3) Rest interval between exercises and sets: \~3 minutes (Warm-up: 1 set of 5 repetitions for each exercise at 50% 1RM)
High-intensity barbell resistance exercise	Resistance exercise	Exercise: Barbell squat, barbell press, and barbell deadlift Number of sets: 3 Number of repetitions: 5 Intensity: 78% 1RM Training method: Circuit training (Squat set 1 ➔ Press set 1 ➔ Deadlift set 1 ➔ Squat set 2 ➔ Press set 2 ➔ Deadlift set 2 ➔ Squat set 3 ➔ Press set 3 ➔ Deadlift set 3) Rest interval between exercises and sets: \~3 minutes (Warm-up: 1 set of 5 repetitions for each exercise at 50% 1RM)

Primary Outcome Measures

Name	Time	Method
Information processing speed (change between baseline and 5 minutes after intervention/control)	Baseline (before intervention) and 5 minutes after intervention/control.	The Information processing speed will be the mean simple reaction time. Lower scores mean a better outcome.
Information processing speed (change between baseline and 35 minutes after intervention/control)	Baseline (before intervention) and 35 minutes after intervention/control.	The Information processing speed will be the mean simple reaction time. Lower scores mean a better outcome.
Inhibitory control (change between baseline and 5 minutes after intervention/control)	Baseline (before intervention) and 5 minutes after (post-task) intervention/control.	The Inhibitory control (Stroop interference score) will be the mean incongruent reaction time minus the mean congruent reaction time. Lower scores mean a better outcome.
Inhibitory control (change between baseline and 35 minutes after intervention/control)	Baseline (before intervention) and 35 minutes after (post-task) intervention/control.	The Inhibitory control (Stroop interference score) will be the mean incongruent reaction time minus the mean congruent reaction time. Lower scores mean a better outcome.
Information processing speed (change between baseline and 20 minutes after intervention/control)	Baseline (before intervention) and 20 minutes after intervention/control.	The Information processing speed will be the mean simple reaction time. Lower scores mean a better outcome.
Inhibitory control (change between baseline and 20 minutes after intervention/control)	Baseline (before intervention) and 20 minutes after (post-task) intervention/control.	The Inhibitory control (Stroop interference score) will be the mean incongruent reaction time minus the mean congruent reaction time. Lower scores mean a better outcome.
Inhibitory control (change between baseline and 50 minutes after intervention/control)	Baseline (before intervention) and 50 minutes after (post-task) intervention/control.	The Inhibitory control (Stroop interference score) will be the mean incongruent reaction time minus the mean congruent reaction time. Lower scores mean a better outcome.
Information processing speed (change between baseline and 50 minutes after intervention/control)	Baseline (before intervention) and 50 minutes after intervention/control.	The Information processing speed will be the mean simple reaction time. Lower scores mean a better outcome.

Secondary Outcome Measures

Name	Time	Method
Epinephrine (change between baseline and 15 minutes after intervention/control)	Baseline and 15 minutes after intervention/control.	Plasma epinephrine concentrations will be measured in duplicate using a commercially available enzyme-linked immunosorbent assay (ELISA) kit.
Epinephrine (change between baseline and 30 minutes after intervention/control)	Baseline and 30 minutes after intervention/control.	Plasma epinephrine concentrations will be measured in duplicate using a commercially available enzyme-linked immunosorbent assay (ELISA) kit.
Epinephrine (change between baseline and immediately after intervention/control)	Baseline and immediately after intervention/control.	Plasma epinephrine concentrations will be measured in duplicate using a commercially available enzyme-linked immunosorbent assay (ELISA) kit.
Epinephrine (change between baseline and 45 minutes after intervention/control)	Baseline and 45 minutes after intervention/control.	Plasma epinephrine concentrations will be measured in duplicate using a commercially available enzyme-linked immunosorbent assay (ELISA) kit.
Epinephrine (change between baseline and 60 minutes after intervention/control)	Baseline and 60 minutes after intervention/control.	Plasma epinephrine concentrations will be measured in duplicate using a commercially available enzyme-linked immunosorbent assay (ELISA) kit.