title: Differential impact of acute high-intensity exercise on circulating endothelial microparticles and insulin resistance between overweight/obese males and females.
abstract: BACKGROUND
  An acute bout of exercise can improve endothelial function and insulin sensitivity when measured on the day following exercise. Our aim was to compare acute high-intensity continuous exercise (HICE) to high-intensity interval exercise (HIIE) on circulating endothelial microparticles (EMPs) and insulin sensitivity in overweight/obese men and women.
  
  
  METHODS
  Inactive males (BMI = 30 ± 3, 25 ± 6 yr, n = 6) and females (BMI = 28 ± 2, 21 ± 3 yr, n = 7) participated in three experimental trials in a randomized counterbalanced crossover design: 1) No exercise control (Control); 2) HICE (20 min cycling @ just above ventilatory threshold); 3) HIIE (10 X 1-min @ ∼ 90% peak aerobic power). Exercise conditions were matched for external work and diet was controlled post-exercise. Fasting blood samples were obtained ∼ 18 hr after each condition. CD62E(+) and CD31(+)/CD42b- EMPs were assessed by flow cytometry and insulin resistance (IR) was estimated by homeostasis model assessment (HOMA-IR).
  
  
  RESULTS
  There was a significant sex X exercise interaction for CD62E(+) EMPs, CD31(+)/CD42b- EMPs, and HOMA-IR (all P < 0.05). In males, both HICE and HIIE reduced EMPs compared to Control (P ≤ 0.05). In females, HICE increased CD62E(+) EMPs (P < 0.05 vs. Control) whereas CD31(+)/CD42b- EMPs were unaltered by either exercise type. There was a significant increase in HOMA-IR in males but a decrease in females following HIIE compared to Control (P<0.05).
  
  
  CONCLUSIONS
  Overweight/obese males and females appear to respond differently to acute bouts of high-intensity exercise. A single session of HICE and HIIE reduced circulating EMPs measured on the morning following exercise in males but in females CD62E(+) EMPs were increased following HICE. Next day HOMA-IR paradoxically increased in males but was reduced in females following HIIE. Future research is needed to investigate mechanisms responsible for potential differential responses between males and females.
authors.affiliation: School of Health and Exercise Sciences, University of British Columbia, Okanagan Campus, Kelowna, British Columbia, Canada.
authors.forename: Cody
authors.initials: C
authors.lastname: Durrer
authors.affiliation: School of Health and Exercise Sciences, University of British Columbia, Okanagan Campus, Kelowna, British Columbia, Canada.
authors.forename: Emily
authors.initials: E
authors.lastname: Robinson
authors.affiliation: School of Health and Exercise Sciences, University of British Columbia, Okanagan Campus, Kelowna, British Columbia, Canada.
authors.forename: Zhongxiao
authors.initials: Z
authors.lastname: Wan
authors.affiliation: College of Education, University of South Florida, Tampa, Florida, United States of America.
authors.forename: Nic
authors.initials: N
authors.lastname: Martinez
authors.affiliation: College of Education, University of South Florida, Tampa, Florida, United States of America.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Hummel
authors.affiliation: Department of Kinesiology, University of Georgia, Athens, Georgia, United States of America.
authors.forename: Nathan T
authors.initials: NT
authors.lastname: Jenkins
authors.affiliation: College of Education, University of South Florida, Tampa, Florida, United States of America.
authors.forename: Marcus W
authors.initials: MW
authors.lastname: Kilpatrick
authors.affiliation: School of Health and Exercise Sciences, University of British Columbia, Okanagan Campus, Kelowna, British Columbia, Canada.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Little
mesh_terms: D000328:Adult; D055252:Cell-Derived Microparticles / Q000473:pathology*; D018592:Cross-Over Studies; D004730:Endothelium, Vascular / Q000473:pathology*; D015444:Exercise; D005081:Exercise Therapy; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D009765:Obesity / Q000097:blood* / Q000628:therapy; D050177:Overweight / Q000097:blood* / Q000628:therapy; D011897:Random Allocation; D012737:Sex Factors