Exercise Neuroscience Flashcards
PHYSICAL ACTIVITY (PA)
- any activity involving movement of body that increases HR/energy expenditure above resting
EXERCISE
- structured/planned PA aimed to improve strength/fitness
LOW INTENSITY EXERCISE
- activity < 3 METS (metabolic equivalents)
- 1 MET = amount of oxygen consumed while sitting at rest
- ie. casual walking; gardening; leisurely sports; golf; light yardwork; house work
MODERATE INTENSITY EXERCISE
- 3-6 METS/50-70% Heart Rate Reserve (HRR)
- ie. brisk walking (3.5+ MPH); yoga; gymnastics; low impact aerobics; weight training; moderate dancing
HIGH INTENSTY EXERCISE (VIGOROUS)
- 6+ METS/70-85% (+) Heart Rate Reserve (HRR)
- ie. running; swimming; soccer; high impact aerobics; circuit weight training; race walking
MEASURING EXERCISE INTENSITY
- heart rate reserve (HRR) = % x maximum heart rate (220 - age)
EXAMPLE - age = 25
- maximum HR: 220 - 25 = 195
- HRR moderate: 50% x 195 = 97.5
- HRR vigorous: 70% x 195 = 136.5
BORG RPE SCALE
- perceived exertion; 1-10:
0 = rest
1 = really easy
2 = easy
3 = moderate
4 = sort of hard
5/6 = hard
7/8 = really hard
9 = really, really hard
10 = maximum
PHYSICAL ACTIVITY FOR ADULTS & OLDER ADULTS
- benefits health
- improves sleep
- maintains healthy weight
- manages stress
- improves quality of life
- reduces chance of: type 2 diabetes (-40%); cardivascular (-35%); depression (-30%); joing/back pain (-25%); cancers (-20%)
- some is good; more is better
ADULT EXERCISE GUIDELINES
- minimise sedentary time; break up periods of inactivity
- be active 150 min moderately (ie. swimming/cycling)/75 min vigorously p/week (ie. running)
- dance/tai chi/bowling x2 p/week = reduce chance of fraility/falls (aka. improve balance) in older adults
- gym/yoga/weight lifting x2 p/week = keeps muscles/bones/joints strong (aka. builds strength)
- 1/3 (34%) men & 1/2 (42%) women DON’T meet said guidelines
MOREAU & CHOU (2019)
- acute effect of high-intensity exercise on executive function (meta-analysis)
- high-intensity exercise (77% + HHR) = small sig facilitating effect on executive function post exercise
LUDYGA ET AL. (2016)
- acute effects of moderate aerobic exercise on specific aspects of executive function in dif age/fitness groups (meta-analysis)
- moderate intensity exercise = small effect on executive function task performance (g = .35)
LOWE, KOLEV & HALL (2016)
- 20 min of moderate intensity aerobic exercise -> improved executive function task performance
LOWE, STAINES & HALL (2017)
- aerobic exercise can promote recovery from fluctuations in dIPFC activity
- n = 28; 100% women; completed 20 min moderate/v light exercise
- speed/incline = adjusted to reach target HR
- THR = RHR + (TI x (220 - age) - RHR)
- post-stimulation: moderate > v light stroop interference
- post-exercise: v light > moderate stroop interference
MANOCCHIO & LOWE (2021)
- aerobic exercise can protect against fluctuations in dIPFC activity
- n = 22; 62% women; completed 20 min moderate/v light exercise
- speed/incline = adjusted to reach target HR
- THR = RHR + (TI x (220 - age) - RHR)
- moderate: change between baseline VS post-exercise interference > v light
ASSOCIATION NETWORKS AFFECTED BY AGING
- executive control network (ECN)
- dorsal attention network (DAN)
- salience (SAL) network
- default network (DN)
MEMORY OUTCOMES POST TRAINING
- improved for aerobic group:
1. word list recall = 29% (4/14)
2. story recall = 33% (2/6)
3. relational = 75% (3/4) - NO improvement:
1. visuospatial = 0% (0/2)
SENSITIVE MEMORY OUTCOMES ACROSS AGE GROUPS & DESIGNS
- YOUNG > OLD
- functional connectivity = stronger for younger adults
- thickness indicates connection strength
- positively related w/fitness; sig correlation for functional connectivity between nodes/fitness; thickness indicates correlation strength
SCHAEFFER ET AL. (2014)
- 8-month exercise intervention alters frontotemporal white matter integrity in overweight kids
- intervention increases frontotemporal white matter tract integrity
STEVENTON ET AL. (2021)
- changes in white matter microstructure/MRI-derived cerebral blood flow post 1-week of exercise training
- exercise = beneficial for vascular plasticity in hippocampus; possibly mediated by brain-derived neurotrophic factor (BDNF) lvls
STEVENTON ET AL. (2021): METHODS
- 15 health young males completed 5 supervised exercise training sessions over 7 days; followed by MRI (diffusion/perfusion weighted & dual-calibrated functional) 1 week apart & blood sampling for BDNF
STEVENTON ET AL. (2021): RESULTS
- diffusion tractography analysis = (post-exercise) sig reduction relative to baseline in restricted fraction (axon-specific metric) in corpus callosum/uncinate fasciculus/parahippocampal cingulum
- voxel-based approach = increase in fractional anisotropy & reduction in radial diffusivity symmetrically in vowels predominantly in corpus collosum
- selective increase in hippocampal blood flow found post-exercise w/no change in vascular reactivity
- BDNF lvls = not altered
STEVENTON ET AL. (2021): CONCLUSIONS
- 1 week of exercise = sufficient to induce microstructural/vascular brain changes on group lvl (independent of BDNF)
- aka. provides new insight into temporal dynamics of plasticity necessary to explot therapeutic exercise potential
PREFRONTAL CORTEX
- increased resting state functional connectivity between left VS right DLPFC & superior parital gyrus/precuneus post 6-month prorgam (45 min cycling x2 p/week)
MECHANISMS OF ACTION
- cerebral blood flow
- systematic inflammation
- vascular health
- neurotransmitters & hormones
YANAGISAWA ET AL. (2010)
- acute moderate exercise elicits increased dorsolateral prefrontal activation
- improves cognitive performance w/Stroop test
MORIARTY ET AL. (2019)
- exercise intensity influences prefrontal cortex oxygenation during cognitive testing
- physical exercise -> increases pro-inflammatory cytokines
HORMONES RELEASED W/PA
- adrenaline
- noradrenaline
- dopamine
- serotonin
- gamma amino butyric acid
- glutamate
- BDNF/VEGF/IGF-1
ENDORPHINS - enkaphalins
- dynorphins
PA RESULTS
IMPROVED SYNAPTOGENESIS
- synapse strength
- receptor concentration
- dendrite spine formation
IMPROVED BRAIN HEALTH
- trophic factors
- blood flow
- immune system
- neurogenesis
IMPROVED BEHAVIOUR
- motor/cognitive beh
- mood/motivation
BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF)
- crucial biological link (aka. “master molecule”)
- improved function of neurons
- encourages new neurons to grow
- protects neurons from stress/cell death
IMMEDIATE EFFECTS OF HIGH INTENSITY EXERCISE (HIE) ON CIRCULATING BDNF LVLS IN YOUNG ADULTS
- systematic review; incl. 22 studies (552 adults 20-31y); meta-analysis = 10 RCTs
- higher BDNF lvls observed when HIE interventions compared w/nonexercise/light intensity exercise
- no sig increase of BDNF observed when HIE compared to moderate-intensity exercise
- HIE causes sig increase on serum BDNF lvls; 95% CI = 4866 to 11,828
DALY, MCMINN & ALLAN (2014)
- bidirectional relationship between physical activity & executive function in older adults
- higher lvls of physical activity associated w/better executive functioning (B = .05; SE = .01; t = 8.52; p = .001)
- high lvls of executive function predicted longitudinal increase in physical activity lvls (B = .05; SE = .01; t = 6.54; p < .001) while adjusting for age/gender/education/wealth/long-standing illness
- within-person changes in executive functioning = associated w/within-person changes in physical activity lvls (B = .03; SE = .01; t = 4.49; p < .001)
LATERAL PFC
- lateral PFC volumes predict exercise adherence
- gray matter volume in IPFC predicted exercise class attendance in older women