title: Kinetics of lactate metabolism after submaximal ergometric exercise in HIV-infected patients.
abstract: OBJECTIVE
  It is unknown whether high levels of lactate result from enhanced production or decreased degradation. We therefore investigated differences in the kinetics of plasma lactic acid in HIV-infected patients receiving or not receiving highly active antiretroviral therapy (HAART) and in uninfected controls after submaximal ergometric exercise.
  
  
  METHODS
  Ten healthy controls, 11 HIV-infected therapy-naïve patients, 15 HIV-infected patients on HAART with normal baseline lactate levels, and nine HIV-infected patients on HAART with elevated baseline lactate levels >2 mmol/L performed 10 min of ergometric exercise, with a heart rate of 200 beats/min minus age. Lactate levels were measured at baseline, at the end of exercise and 15, 30, 45, 60 and 120 min thereafter.
  
  
  RESULTS
  Mean baseline lactate levels were 1.4, 1.5, 1.5 and 2.8 mmol/L in the controls, the therapy-naïve patients, the patients on HAART with normal lactate levels and the patients on HAART with elevated lactate levels, respectively. Maximum lactate levels after exercise were similar in all groups (9.7, 9.4, 9.0 and 10.1 mmol/L, respectively). Significant differences were found in the slope of lactate decline between controls and untreated individuals (P=0.038) and between patients on HAART with normal baseline lactate and patients on HAART with elevated baseline lactate (P=0.028).
  
  
  CONCLUSIONS
  Differences in lactate metabolism do exist between healthy controls and HIV-infected therapy-naïve individuals. Thus, HIV infection in itself may influence lactate levels. Elevated baseline lactate levels are associated with a delayed decline of lactate after exercise. These results could be explained by impaired lactate clearance. Lactate production upon exercise does not seem to be affected by baseline lactate levels.
authors.affiliation: Department of Infectious Diseases, Medizinische Poliklinik, University Hospital of Munich, Pettenkoferstrasse 8a, 80336 Munich, Germany.
authors.forename: A-M
authors.initials: AM
authors.lastname: Bauer
authors.forename: T
authors.initials: T
authors.lastname: Sternfeld
authors.forename: S
authors.initials: S
authors.lastname: Horster
authors.forename: M
authors.initials: M
authors.lastname: Schunk
authors.forename: F-D
authors.initials: FD
authors.lastname: Goebel
authors.forename: J R
authors.initials: JR
authors.lastname: Bogner
mesh_terms: D000328:Adult; D023241:Antiretroviral Therapy, Highly Active; D016022:Case-Control Studies; D016552:Ergometry; D015444:Exercise; D005260:Female; D015658:HIV Infections / Q000188:drug therapy / Q000378:metabolism* / Q000503:physiopathology; D006801:Humans; D019344:Lactic Acid / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D018894:Reverse Transcriptase Inhibitors / Q000627:therapeutic use; D018709:Statistics, Nonparametric
chemical_list: D018894:Reverse Transcriptase Inhibitors; D019344:Lactic Acid