title: Four weeks of normobaric "live high-train low" do not alter muscular or systemic capacity for maintaining pH and K⁺ homeostasis during intense exercise.
abstract: It was investigated if athletes subjected to 4 wk of living in normobaric hypoxia (3,000 m; 16 h/day) while training at 800-1,300 m ["live high-train low" (LHTL)] increase muscular and systemic capacity for maintaining pH and K(+) homeostasis as well as intense exercise performance. The design was double-blind and placebo controlled. Mean power during 30-s all-out cycling was similar before and immediately after LHTL (650 ± 31 vs. 628 ± 32 W; n = 10) and placebo exposure (658 ± 22 vs. 660 ± 23 W; n = 6). Supporting the performance data, arterial plasma pH, lactate, and K(+) during submaximal and maximal exercise were also unaffected by the intervention in both groups. In addition, muscle buffer capacity (in mmol H(+)·kg dry wt(-1)·pH(-1)) was similar before and after in both the LHTL (140 ± 12 vs. 140 ± 16) and placebo group (145 ± 2 vs. 140 ± 3). The expression of sarcolemmal H(+) transporters (Na(+)/H(+) exchanger 1, monocarboxylate transporters 1 and 4), as well as expression of Na(+)-K(+) pump subunits-α(1), -α(2), and -β(1) was also similar before and after the intervention. In conclusion, muscular and systemic capacity for maintaining pH and K(+) balance during exercise is similar before and after 4 wk of placebo-controlled normobaric LHTL. In accordance, 30-s all-out sprint ability was similar before and after LHTL.
authors.affiliation: Center for Integrative Human Physiology (ZIHP) University of Zurich, Zurich, Switzerland.
authors.forename: N B
authors.initials: NB
authors.lastname: Nordsborg
authors.forename: C
authors.initials: C
authors.lastname: Siebenmann
authors.forename: R A
authors.initials: RA
authors.lastname: Jacobs
authors.forename: P
authors.initials: P
authors.lastname: Rasmussen
authors.forename: V
authors.initials: V
authors.lastname: Diaz
authors.forename: P
authors.initials: P
authors.lastname: Robach
authors.forename: C
authors.initials: C
authors.lastname: Lundby
mesh_terms: D000328:Adult; D000531:Altitude; D001639:Bicarbonates / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods; D005260:Female; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D000860:Hypoxia / Q000378:metabolism / Q000503:physiopathology; D019344:Lactic Acid / Q000378:metabolism; D007811:Lanthanum / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D011188:Potassium / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013647:Task Performance and Analysis
chemical_list: D001639:Bicarbonates; D002245:Carbon Dioxide; D019344:Lactic Acid; D007811:Lanthanum; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium