title: Physiologic alterations and predictors of performance in a 160-km ultramarathon.
abstract: OBJECTIVE
  To describe physiologic alterations in runners competing in a 160-km endurance event and to evaluate the utility of weight and blood pressure measurements in the assessment of runner performance.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  One hundred sixty-km ultramarathon.
  
  
  METHODS
  Ninety-one of the 101 participants in the 2010 Tahoe Rim 100 Mile Endurance Run.
  
  
  METHODS
  Brachial blood pressure, heart rate, and weight were assessed before competition, at 80 km, and at 160 km.
  
  
  METHODS
  Alterations in brachial blood pressure, heart rate, and weight were assessed in finishers. Weight loss, brachial blood pressure, pulse pressure, and heart rate at 80 km were assessed in all participants for their ability to predict failure to finish the race.
  
  
  RESULTS
  Participants who finished 160 km (57%) experienced their fastest heart rates (P < 0.05), lowest systolic pressures (P < 0.05), highest diastolic pressures (P < 0.05), narrowest pulse pressures (P < 0.05), and lowest weights (P < 0.05) at 80 km. High rates of finishing were seen in those who lost >5% of their prerace weight (87%). Categorical weight loss (<3%, 3%-5%, and >5%) was not associated with the ability to finish (P > 0.05) or finishing time (P > 0.05), whereas the presence of a narrow pulse pressure was associated with a high likelihood (likelihood ratio = 9.84; P = 0.002) of failure to finish.
  
  
  CONCLUSIONS
  Greater intracompetition weight loss is not associated with impaired performance but rather may be an aspect of superior performance. Narrow pulse pressure was associated with a high likelihood of failure to finish.
authors.affiliation: Department of Medicine, University of California, San Francisco, San Francisco, California, USA. Zachary.Landman@ucsf.edu
authors.forename: Zachary C
authors.initials: ZC
authors.lastname: Landman
authors.forename: Geri O
authors.initials: GO
authors.lastname: Landman
authors.forename: Pedram
authors.initials: P
authors.lastname: Fatehi
mesh_terms: D000328:Adult; D054874:Athletic Performance / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D016013:Likelihood Functions; D008297:Male; D008875:Middle Aged; D010807:Physical Endurance / Q000502:physiology; D011446:Prospective Studies; D012420:Running / Q000502:physiology*; D055815:Young Adult