Effects of nitrate supplementation in trained and untrained muscle are modest with initial high plasma nitrite levels

Nitrate () supplementation resulting in higher plasma nitrite () is reported to lower resting mean arterial blood pressure (MAP) and oxygen uptake (VO₂) during submaximal exercise in non‐athletic populations, whereas effects in general are absent in endurance‐trained individuals. To test whether physiologic effects of supplementation depend on local muscular training status or cardiovascular fitness, male endurance‐trained cyclists (CYC, n=9, VO₂‐max: 64±3 mL/min/kg; mean±SD) and recreational active subjects serving as a control group (CON, n=8, 46±3 mL/min/kg), acutely consumed nitrate‐rich beetroot juice (] ~9 mmol) (NIT) or placebo (PLA) with assessment of resting MAP and energy expenditure during moderate intensity (~50% VO₂‐max) and incremental leg cycling (LEG‐ex) and arm‐cranking exercise (ARM‐ex). NIT increased (P<.001) resting plasma by ~1200% relative to PLA. Plasma increased ~25% (P<.01) with a significant change only in CYC. LEG‐ex VO₂ (~2.60 L/min), ARM‐ex VO₂ (~1.14 L/min), and resting MAP (~87 mm Hg) remained unchanged for CYC, and similarly for CON, no changes were observed for LEG‐ex VO₂ (~2.03 L/min), ARM‐ex VO₂ (~1.06 L/min), or resting MAP (~85 mm Hg). VO₂‐max was not affected by supplementation, but incremental test peak power was higher (P<.05) in LEG‐ex for CYC in NIT relative to PLA (418±47 vs 407±46 W). In both CYC and CON, high initial baseline values and small increases in plasma after NIT may have lowered the effect of the intervention implying that muscular and cardiovascular training status is likely not the only factors that influence the physiologic effects of supplementation.