title: The effects of high-intensity exercise on neural responses to images of food.
abstract: BACKGROUND
  Acute bouts of high-intensity exercise modulate peripheral appetite regulating hormones to transiently suppress hunger. However, the effects of physical activity on central appetite regulation have yet to be fully investigated.
  
  
  OBJECTIVE
  We used functional magnetic resonance imaging (fMRI) to compare neural responses to visual food stimuli after intense exercise and rest.
  
  
  METHODS
  Fifteen lean healthy men [mean ± SD age: 22.5 ± 3.1 y; mean ± SD body mass index (in kg/m(2)): 24.2 ± 2.4] completed two 60-min trials-exercise (EX; running at ∼70% maximum aerobic capacity) and a resting control trial (REST)-in a counterbalanced order. After each trial, an fMRI assessment was completed in which images of high- and low-calorie foods were viewed.
  
  
  RESULTS
  EX significantly suppressed subjective appetite responses while increasing thirst and core-body temperature. Furthermore, EX significantly suppressed ghrelin concentrations and significantly enhanced peptide YY release. Neural responses to images of high-calorie foods significantly increased dorsolateral prefrontal cortex activation and suppressed orbitofrontal cortex (OFC) and hippocampus activation after EX compared with REST. After EX, low-calorie food images increased insula and putamen activation and reduced OFC activation compared with REST. Furthermore, left pallidum activity was significantly elevated after EX when low-calorie images were viewed and was suppressed when high-calorie images were viewed, and these responses correlated significantly with thirst.
  
  
  CONCLUSIONS
  Exercise increases neural responses in reward-related regions of the brain in response to images of low-calorie foods and suppresses activation during the viewing of high-calorie foods. These central responses are associated with exercise-induced changes in peripheral signals related to appetite-regulation and hydration status. This trial was registered at www.clinicaltrials.gov as NCT01926431.
authors.affiliation: University of Aberdeen, Rowett Research Institute, Aberdeen, United Kingdom (DRC); the Department of Investigative Medicine, Imperial College London, London, United Kingdom (ESC); the Human Brain Physiology and Stimulation Laboratory, Johns Hopkins University, Baltimore, MD (RMH); and the School of Sport and Exercise Sciences, University of Birmingham, Birmingham, United Kingdom (AKB).
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Crabtree
authors.forename: Edward S
authors.initials: ES
authors.lastname: Chambers
authors.forename: Robert M
authors.initials: RM
authors.lastname: Hardwick
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Blannin
mesh_terms: D000293:Adolescent; D000328:Adult; D001066:Appetite / Q000502:physiology*; D001069:Appetite Regulation / Q000502:physiology; D015992:Body Mass Index; D002755:Choice Behavior / Q000502:physiology; D018592:Cross-Over Studies; D002149:Energy Intake; D015444:Exercise / Q000502:physiology*; D005260:Female; D005502:Food; D005518:Food Preferences / Q000523:psychology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D010775:Photic Stimulation; D017397:Prefrontal Cortex / Q000502:physiology*; D012201:Reward; D055815:Young Adult