title: Associations Between Physical Fitness Indices and Working Memory in Breast Cancer Survivors and Age-Matched Controls.
abstract: BACKGROUND
  This study examined the effects of cardiorespiratory fitness, heart rate recovery, and physical activity on working memory in breast cancer survivors and age-matched controls.
  
  
  METHODS
  Using a case-control design, 32 women who had received a breast cancer diagnosis and completed primary treatment within the past 36-months (11 radiation only; 21 chemotherapy) and 30 age-matched women with no previous cancer diagnosis completed a n-back continuous performance task commonly used as an assessment of working memory. In addition, cardiorespiratory fitness and heart rate recovery were measured during a submaximal graded exercise test and physical activity was measured using 7-days of accelerometer monitoring.
  
  
  RESULTS
  Breast cancer survivors who had received chemotherapy had poorer heart rate recovery (p = .010) and engaged in less physical activity than women who had received radiation only (p = .004) or non-cancer controls (p = .029). Cancer treatment (radiation; chemotherapy) predicted differences in reaction times on the 1-back working memory task (p = .029). However, more rapid heart rate recovery predicted shorter reaction times on the 1-back task in the age-matched control group (p = .002). All participants with greater cardiorespiratory fitness displayed greater accuracy independent of disease status on the 1-back task (p = .017). No significant group differences in reaction times were observed for 2-back target trials between breast cancer survivors and controls. However, greater total physical activity predicted shorter reaction times in breast cancer survivors (radiation, chemotherapy) on the 2-back task (p = .014). In addition, all participants who exhibited more rapid heart rate recovery demonstrated better greater accuracy regardless of disease status (p = .013).
  
  
  CONCLUSIONS
  These findings support differences in physical activty participation, heart rate recovery, and 1- and 2-back working memory reaction times between breast cancer survivors and age-matched controls. Greater cardiorespiratory fitness, heart rate recovery, and physical activity were positively associated with better working memory performance across conditions.
authors.affiliation: 1 Department of Behavioral Health and Nutrition, College of Health Sciences, University of Delaware , Newark, Deleware.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Mackenzie
authors.affiliation: 2 School of Family and Consumer Science, Texas State University-San Marcos , San Marcos, Texas.
authors.forename: Krystle E
authors.initials: KE
authors.lastname: Zuniga
authors.affiliation: 3 Department of Kinesiology and Community Health, College of Applied Health Sciences, University of Illinois at Urbana-Champaign , Urbana, Illinois.
authors.forename: Lauren B
authors.initials: LB
authors.lastname: Raine
authors.affiliation: 3 Department of Kinesiology and Community Health, College of Applied Health Sciences, University of Illinois at Urbana-Champaign , Urbana, Illinois.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Awick
authors.affiliation: 3 Department of Kinesiology and Community Health, College of Applied Health Sciences, University of Illinois at Urbana-Champaign , Urbana, Illinois.
authors.forename: Charles H
authors.initials: CH
authors.lastname: Hillman
authors.affiliation: 4 Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign , Urbana, Illinois.
authors.forename: Arthur F
authors.initials: AF
authors.lastname: Kramer
authors.affiliation: 3 Department of Kinesiology and Community Health, College of Applied Health Sciences, University of Illinois at Urbana-Champaign , Urbana, Illinois.
authors.forename: Edward
authors.initials: E
authors.lastname: McAuley
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000453:epidemiology / Q000523:psychology* / Q000628:therapy; D016022:Case-Control Studies; D015444:Exercise; D005080:Exercise Test; D005260:Female; D006304:Health Status; D006305:Health Status Indicators; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D010809:Physical Fitness / Q000502:physiology* / Q000523:psychology; D011788:Quality of Life; D011878:Radiotherapy; D017741:Survivors / Q000523:psychology* / Q000706:statistics & numerical data; D055815:Young Adult
chemical_list: D000970:Antineoplastic Agents