title: Whole body heat stress increases motor cortical excitability and skill acquisition in humans.
abstract: OBJECTIVE
  Vigorous systemic exercise stimulates a cascade of molecular and cellular processes that enhance central nervous system (CNS) plasticity and performance. The influence of heat stress on CNS performance and learning is novel. We designed two experiments to determine whether passive heat stress (1) facilitated motor cortex excitability and (2) improved motor task acquisition compared to no heat stress.
  
  
  METHODS
  Motor evoked potentials (MEPs) from the first dorsal interosseus (FDI) were collected before and after 30 min of heat stress at 73 °C. A second cohort of subjects performed a motor learning task using the FDI either following heat or the no heat condition.
  
  
  RESULTS
  Heat stress increased heart rate to 65% of age-predicted maximum. After heat, mean resting MEP amplitude increased 48% (p<0.05). MEP stimulus-response amplitudes did not differ according to stimulus intensity. In the second experiment, heat stress caused a significant decrease in absolute and variable error (p<0.05) during a novel movement task using the FDI.
  
  
  CONCLUSIONS
  Passive environmental heat stress (1) increases motor cortical excitability, and (2) enhances performance in a motor skill acquisition task.
  
  
  CONCLUSIONS
  Controlled heat stress may prime the CNS to enhance motor skill acquisition during rehabilitation.
authors.affiliation: Department of Physical Therapy, Rueckert-Hartman College for Health Professions, Regis University, Denver, CO 80221, USA.
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Littmann
authors.affiliation: Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, 1-252 Medical Education Building, Iowa City, IA 52242-1190, USA. Electronic address: richard-shields@uiowa.edu.
authors.forename: Richard K
authors.initials: RK
authors.lastname: Shields
mesh_terms: D000328:Adult; D001831:Body Temperature / Q000502:physiology*; D015331:Cohort Studies; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D018869:Heat-Shock Response / Q000502:physiology*; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D009048:Motor Skills / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D010865:Pilot Projects; D055815:Young Adult
keywords: Cortical excitability; Heat stress; Motor learning