The effects of 2 days of intermittent exogenous ketosis at high altitude on baroreflex sensitivity and ventilation under hypoxic and hypercapnic conditions

Narang, Benjamin J. (avtor), Tominec, Domen (avtor), Stalmans, Myrthe (avtor), Millet, Grégoire P. (avtor), Poffé, Chiel (avtor), Debevec, Tadej (avtor)

High-altitude (HA) exposure induces an integrated physiological response to mitigate hypoxemia. Exogenous ketosis at simulated HA was previously shown to accentuate sympathetic activation and attenuate pulse oxygen saturation (Sp$_{O2}$) decreases through hyperventilation. The aim of this study was to extend these findings by investigating the effects of intermittent exogenous ketosis (IEK) across 2 days at terrestrial HA (3,375 m) on baroreflex sensitivity, heart rate variability, and hypoxic/hypercapnic ventilatory responses. Thirty-four healthy active adults completed neutral, hypoxic, and hypercapnic (0.03 FI$_{CO2}$) exposures, each comprising 6 min of seated rest, once at sea level (SL) and once after 2 days at HA. Across the 2 days, participants intermittently ingested either ketone monoester supplements (IEK) or placebo (PLA). During each exposure, blood pressure, ventilation, Sp$_{O2}$, and end-tidal CO$_2$ pressure (PET$_{CO2}$) were continuously recorded, and arterialized capillary blood gas content was measured in the final 30 s. Baroreflex sensitivity and time-domain metrics of heart rate variability were reduced at HA (P = 0.006–0.043) but unaffected by group (P = 0.288–0.525). However, ventilation at HA under all three conditions was significantly higher in IEK compared with PLA (all P < 0.001). In hypoxia, this induced a higher Sp$_{O2}$ (P = 0.038) and capillary O$_2$ pressure (P = 0.003). In hypercapnia, this induced a lower PET$_{CO2}$ and capillary CO$_2$ tension (both P < 0.001). These results extend previous findings, suggesting that IEK enhances ventilation at terrestrial HA after 2 days of exposure, with this effect being independent from baroreflex sensitivity or heart rate variability changes.

• Jezik: Angleški jezik
• Ključne besede: automatic control, blood pressure, hypobaric hypoxia, ketone bodies, sympathetic nervous system, high altitude
• Vrsta gradiva: Članek v reviji
• Tipologija: 1.01 - Izvirni znanstveni članek
• Organizacija: FŠ - Fakulteta za šport
• Status publikacije: Objavljeno
• Različica publikacije: Objavljena publikacija
• Leto izida: 2025
• Št. strani: Str. R350-R362
• Številčenje: Vol. 329, iss. 2
• PID: 20.500.12556/RUL-183685
• UDK: 612
• ISSN pri članku: 1522-1490
• DOI: 10.1152/ajpregu.00125.2025
• COBISS.SI-ID: 243716867
• Datum objave v RUL: 17.06.2026

Gradivo je del revije

• Naslov: American journal of physiology : Regulatory, integrative and comparative physiology
• Skrajšan naslov: Am. j. physiol. Regul., integr. comp. physiol.
• Založnik: American Physiological Society
• ISSN: 1522-1490
• COBISS.SI-ID: 3394580

Licence

• Licenca: CC BY 4.0, Creative Commons Priznanje avtorstva 4.0 Mednarodna
• Povezava: http://creativecommons.org/licenses/by/4.0/deed.sl
• Opis: To je standardna licenca Creative Commons, ki daje uporabnikom največ možnosti za nadaljnjo uporabo dela, pri čemer morajo navesti avtorja.

Sekundarni jezik

• Jezik: Slovenski jezik
• Ključne besede: anoksija, krvni tlak, avtomatski nadzor, ketoza, ketonska telesa, hipobarična hipoksija, simpatično živčevje, visoka nadmorska višina