Alteration of Cognitive Function
Conditions
Keywords
exercise, cognition, brain-derived neurotrophic factor, insulin-like growth factor 1, cortisol
Brief summary
The purpose of this study is to determine whether an acute bout of exercise may temporarily enhance cognitive function (such as memory or attention span) by measuring behavioral performance on cognitive tests, as well as expression of hormones in circulation associated with brain plasticity and stress.
Detailed description
This is a randomized experiment consisting of three visits for each participant. Participants are determined to be eligible beforehand during a phone screening, in which the various study inclusions and exclusions are determined and the Physical Activity Readiness Questionnaire for Everyone 2015 (PARQ) is administered. In the first visit, various anthropometric data are collected from participants, such as height, weight, and waist and hip circumference. The participants' blood pressure is also checked for hypertension. The participants are given Dual Energy X-Ray Absorptiometry (DEXA) scans to determine total body composition (bone, fat, and fat-free mass) If the participant is female, a urine analysis to determine pregnancy is required during the visit before the DEXA to ensure safety. Participants are given the Rapid Assessment of Physical Activity (RAPA) questionnaire to assess habitual activity levels. The participants' muscle strength is also measured using the Biodex System 3, an isokinetic dynamometer. The participants then undergo a maximal stress test on a treadmill integrated with a Cardinal Health Metabolic/ECG cart using a modified Balke protocol, beginning at 3 mph, 0% grade, and increasing 2.5% grade every 3 minutes. The ECG component of the metabolic cart will be used for continuous heart rate monitoring as part of the fitness assessment. Cardiorespiratory parameters (VO2, ventilation, respiratory rate) will also be measured throughout the test. Blood pressure is measured during the last 30 seconds of each exercise stage and the rating of perceived exertion (RPE) using the Borg 6 to 20 scale is obtained during each stage. Subjects are urged to give a maximal effort and are pushed until volitional fatigue. In the second visit, participants are first given a series of cognitive tests designed to quantify such cognitive faculties as visual short-term memory, selective attention, processing speed, and verbal fluency. These tests consist of seeing simple images on a computer screen, such as a series of colored shapes, and responding using a keypad. A blood sample is also collected from the participants to serve as a baseline. The subject is then randomized to one of three groups: the first group rests for 30 minutes; the second group walks on the treadmill at a mild intensity, defined as maintaining 60% of the heart rate observed during the max VO2 from the first visit; the last group walks on the treadmill at a hard intensity, defined as maintaining 80% of the heart rate observed during the max VO2 from the first visit. The subjects then undergo a second blood draw after cooling down, followed immediately by another round of the same cognitive tests. An hour after finishing the exercise intervention, the same procedure of blood draw followed by cognitive tests is repeated, and an hour after that it is repeated again. The third visit must be about 24 hours after the previous visit. Participants have blood drawn and one final round of cognitive tests.
Interventions
OTHERExercise Challenge
Participants randomized to an exercise condition will perform treadmill exercise for 30 minutes. Participants will self-select a comfortable walking speed. The treadmill grade will be adjusted to elicit and maintain the target heart rate.
Sponsors
Johns Hopkins University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
* Body mass index (BMI) of between 18.5 and 35 kg/m2 * Normal or corrected-to-normal vision * No contraindications to participation in moderate to hard intensity physical activity
Exclusion criteria
* Self-report of alcohol or substance abuse in the past year or current treatment * Women who are pregnant or nursing * BMI of \< 18.5 or \> 35 kg/m2 * Diabetes mellitus. Subjects will be excluded for diabetes even if controlled by medications * Cigarette smoking in the previous 12 weeks * Elevated blood pressure (BP) defined as systolic BP ≥ 140 mm Hg or diastolic BP ≥ 90 mm Hg * Self-report of cardiovascular disease, cancer, renal disease, and other serious conditions that could be exacerbated by moderate intensity physical activity.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| general executive functioning as assessed by the irrelevant capture task questionnaire | baseline | participants must identify a set of symbols as either letters or numbers while ignoring distracting images that flash on the screen, scored based on accuracy (0-100%) and reaction time in milliseconds |
| visual long-term memory questionnaire | 24 hours after baseline | participants encode images in a cover task at baseline, scored on accuracy (0-100%) |
| verbal fluency | baseline | participants are asked to name as many words as they can that begin with a certain letter within 1 minute, scored on number of appropriate words |
| cortisol in circulation | baseline | in nanograms per milliliter (ng/ml) |
| igf-1 in circulation | baseline | insulin-like growth factor 1 in nanograms per milliliter (ng/ml) |
| bdnf in circulation | baseline | brain-derived neurotrophic factor in nanograms per milliliter (ng/ml) |
| general executive functioning as assessed by the stroop test questionnaire | baseline | participants must identify the color of various words on the screen irrespective of their meaning, scored based on accuracy (0-100%) and reaction time in milliseconds |
| general executive functioning as assessed by the flanker task questionnaire | baseline | participants must identify the orientation of a central arrow while ignoring those of other arrows on the screen, scored based on accuracy (0-100%) and reaction time in milliseconds |
| visual short-term memory questionnaire | baseline | participants are shown sets of colored squares briefly and must pick out the square that changed color after a delay, scored on accuracy (0-100%) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| waist-to-hip ratio | baseline | — |
| habitual activity levels | baseline | as assessed by Rapid Assessment of Physical Activity questionnaire, possible scores are: Active, Under Active Regular, Under Active Regular- Light Activities, Under Active, Sedentary |
| muscle strength | baseline | as measured by isokinetic testing using the Biodex System 3 |
| total and regional bone mass | baseline | as assessed by dual-energy x-ray absorptiometry (DEXA) scan, in grams per square centimeter (g/cm2) |
| total and regional fat and fat-free mass | baseline | as assessed by dual-energy x-ray absorptiometry (DEXA) scan in grams per square centimeter (g/cm2) |
| cardiorespiratory endurance | baseline | as assessed by maximal stress test, represented by heart rate at maximal oxygen uptake |
| body mass index (BMI) | baseline | measured in kilograms per square meter (kg/m2) |
Countries
United States
Outcome results
None listed