Nitrate‐rich beetroot juice ingestion reduces skeletal muscle O2 uptake and blood flow during exercise in sedentary men

M Nyberg; PM Christensen; JR Blackwell; M Hostrup; AM Jones; J Bangsbo

doi:10.1113/jp281995

Nitrate‐rich beetroot juice ingestion reduces skeletal muscle O₂ uptake and blood flow during exercise in sedentary men

M Nyberg, PM Christensen, JR Blackwell, M Hostrup, AM Jones, J Bangsbo

Faculty of Health

University of Exeter

Research output: Contribution to journal › Article › peer-review

Abstract

AbstractDietary nitrate supplementation has been shown to reduce pulmonary O2 uptake during submaximal exercise and enhance exercise performance. However, the effects of nitrate supplementation on local metabolic and haemodynamic regulation in contracting human skeletal muscle remain unclear. To address this, eight healthy young male sedentary subjects were assigned in a randomized, double‐blind, crossover design to receive nitrate‐rich beetroot juice (NO3, 9 mmol) and placebo (PLA) 2.5 h prior to the completion of a double‐step knee‐extensor exercise protocol that included a transition from unloaded to moderate‐intensity exercise (MOD) followed immediately by a transition to intense exercise (HIGH). Compared with PLA, NO3 increased plasma levels of nitrate and nitrite. During MOD, leg and leg blood flow (LBF) were reduced to a similar extent (∼9%–15%) in NO3. During HIGH, leg was reduced by ∼6%–10% and LBF by ∼5%–9% (did not reach significance) in NO3. Leg kinetics was markedly faster in the transition from passive to MOD compared with the transition from MOD to HIGH both in NO3 and PLA with no difference between PLA and NO3. In NO3, a reduction in nitrate and nitrite concentration was detected between arterial and venous samples. No difference in the time to exhaustion was observed between conditions. In conclusion, elevation of plasma nitrate and nitrate reduces leg skeletal muscle and blood flow during exercise. However, nitrate supplementation does not enhance muscle kinetics during exercise, nor does it improve time to exhaustion when exercising with a small muscle mass. imageKey points Dietary nitrate supplementation has been shown to reduce systemic O2 uptake during exercise and improve exercise performance. The effects of nitrate supplementation on local metabolism and blood flow regulation in contracting human skeletal muscle remain unclear. By using leg exercise engaging a small muscle mass, we show that O2 uptake and blood flow are similarly reduced in contracting skeletal muscle of humans during exercise. Despite slower kinetics in the transition from moderate to intense exercise, no effects of nitrate supplementation were observed for kinetics and time to exhaustion. Nitrate and nitrite concentrations are reduced across the exercising leg, suggesting that these ions are extracted from the arterial blood by contracting skeletal muscle.

Original language	English
Pages (from-to)	5203-5214
Number of pages	0
Journal	The Journal of Physiology
Volume	599
Issue number	23
Early online date	14 Oct 2021
DOIs	https://doi.org/10.1113/jp281995
Publication status	Published - Dec 2021

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@article{686abdc0fee64900815b8cab02ba5c8d,

title = "Nitrate‐rich beetroot juice ingestion reduces skeletal muscle O2 uptake and blood flow during exercise in sedentary men",

abstract = "AbstractDietary nitrate supplementation has been shown to reduce pulmonary O2 uptake during submaximal exercise and enhance exercise performance. However, the effects of nitrate supplementation on local metabolic and haemodynamic regulation in contracting human skeletal muscle remain unclear. To address this, eight healthy young male sedentary subjects were assigned in a randomized, double‐blind, crossover design to receive nitrate‐rich beetroot juice (NO3, 9 mmol) and placebo (PLA) 2.5 h prior to the completion of a double‐step knee‐extensor exercise protocol that included a transition from unloaded to moderate‐intensity exercise (MOD) followed immediately by a transition to intense exercise (HIGH). Compared with PLA, NO3 increased plasma levels of nitrate and nitrite. During MOD, leg and leg blood flow (LBF) were reduced to a similar extent (∼9%–15%) in NO3. During HIGH, leg was reduced by ∼6%–10% and LBF by ∼5%–9% (did not reach significance) in NO3. Leg kinetics was markedly faster in the transition from passive to MOD compared with the transition from MOD to HIGH both in NO3 and PLA with no difference between PLA and NO3. In NO3, a reduction in nitrate and nitrite concentration was detected between arterial and venous samples. No difference in the time to exhaustion was observed between conditions. In conclusion, elevation of plasma nitrate and nitrate reduces leg skeletal muscle and blood flow during exercise. However, nitrate supplementation does not enhance muscle kinetics during exercise, nor does it improve time to exhaustion when exercising with a small muscle mass. imageKey points Dietary nitrate supplementation has been shown to reduce systemic O2 uptake during exercise and improve exercise performance. The effects of nitrate supplementation on local metabolism and blood flow regulation in contracting human skeletal muscle remain unclear. By using leg exercise engaging a small muscle mass, we show that O2 uptake and blood flow are similarly reduced in contracting skeletal muscle of humans during exercise. Despite slower kinetics in the transition from moderate to intense exercise, no effects of nitrate supplementation were observed for kinetics and time to exhaustion. Nitrate and nitrite concentrations are reduced across the exercising leg, suggesting that these ions are extracted from the arterial blood by contracting skeletal muscle. ",

author = "M Nyberg and PM Christensen and JR Blackwell and M Hostrup and AM Jones and J Bangsbo",

year = "2021",

month = dec,

doi = "10.1113/jp281995",

language = "English",

volume = "599",

pages = "5203--5214",

journal = "The Journal of Physiology",

issn = "0022-3751",

number = "23",

}

TY - JOUR

T1 - Nitrate‐rich beetroot juice ingestion reduces skeletal muscle O2 uptake and blood flow during exercise in sedentary men

AU - Nyberg, M

AU - Christensen, PM

AU - Blackwell, JR

AU - Hostrup, M

AU - Jones, AM

AU - Bangsbo, J

PY - 2021/12

Y1 - 2021/12

N2 - AbstractDietary nitrate supplementation has been shown to reduce pulmonary O2 uptake during submaximal exercise and enhance exercise performance. However, the effects of nitrate supplementation on local metabolic and haemodynamic regulation in contracting human skeletal muscle remain unclear. To address this, eight healthy young male sedentary subjects were assigned in a randomized, double‐blind, crossover design to receive nitrate‐rich beetroot juice (NO3, 9 mmol) and placebo (PLA) 2.5 h prior to the completion of a double‐step knee‐extensor exercise protocol that included a transition from unloaded to moderate‐intensity exercise (MOD) followed immediately by a transition to intense exercise (HIGH). Compared with PLA, NO3 increased plasma levels of nitrate and nitrite. During MOD, leg and leg blood flow (LBF) were reduced to a similar extent (∼9%–15%) in NO3. During HIGH, leg was reduced by ∼6%–10% and LBF by ∼5%–9% (did not reach significance) in NO3. Leg kinetics was markedly faster in the transition from passive to MOD compared with the transition from MOD to HIGH both in NO3 and PLA with no difference between PLA and NO3. In NO3, a reduction in nitrate and nitrite concentration was detected between arterial and venous samples. No difference in the time to exhaustion was observed between conditions. In conclusion, elevation of plasma nitrate and nitrate reduces leg skeletal muscle and blood flow during exercise. However, nitrate supplementation does not enhance muscle kinetics during exercise, nor does it improve time to exhaustion when exercising with a small muscle mass. imageKey points Dietary nitrate supplementation has been shown to reduce systemic O2 uptake during exercise and improve exercise performance. The effects of nitrate supplementation on local metabolism and blood flow regulation in contracting human skeletal muscle remain unclear. By using leg exercise engaging a small muscle mass, we show that O2 uptake and blood flow are similarly reduced in contracting skeletal muscle of humans during exercise. Despite slower kinetics in the transition from moderate to intense exercise, no effects of nitrate supplementation were observed for kinetics and time to exhaustion. Nitrate and nitrite concentrations are reduced across the exercising leg, suggesting that these ions are extracted from the arterial blood by contracting skeletal muscle.

AB - AbstractDietary nitrate supplementation has been shown to reduce pulmonary O2 uptake during submaximal exercise and enhance exercise performance. However, the effects of nitrate supplementation on local metabolic and haemodynamic regulation in contracting human skeletal muscle remain unclear. To address this, eight healthy young male sedentary subjects were assigned in a randomized, double‐blind, crossover design to receive nitrate‐rich beetroot juice (NO3, 9 mmol) and placebo (PLA) 2.5 h prior to the completion of a double‐step knee‐extensor exercise protocol that included a transition from unloaded to moderate‐intensity exercise (MOD) followed immediately by a transition to intense exercise (HIGH). Compared with PLA, NO3 increased plasma levels of nitrate and nitrite. During MOD, leg and leg blood flow (LBF) were reduced to a similar extent (∼9%–15%) in NO3. During HIGH, leg was reduced by ∼6%–10% and LBF by ∼5%–9% (did not reach significance) in NO3. Leg kinetics was markedly faster in the transition from passive to MOD compared with the transition from MOD to HIGH both in NO3 and PLA with no difference between PLA and NO3. In NO3, a reduction in nitrate and nitrite concentration was detected between arterial and venous samples. No difference in the time to exhaustion was observed between conditions. In conclusion, elevation of plasma nitrate and nitrate reduces leg skeletal muscle and blood flow during exercise. However, nitrate supplementation does not enhance muscle kinetics during exercise, nor does it improve time to exhaustion when exercising with a small muscle mass. imageKey points Dietary nitrate supplementation has been shown to reduce systemic O2 uptake during exercise and improve exercise performance. The effects of nitrate supplementation on local metabolism and blood flow regulation in contracting human skeletal muscle remain unclear. By using leg exercise engaging a small muscle mass, we show that O2 uptake and blood flow are similarly reduced in contracting skeletal muscle of humans during exercise. Despite slower kinetics in the transition from moderate to intense exercise, no effects of nitrate supplementation were observed for kinetics and time to exhaustion. Nitrate and nitrite concentrations are reduced across the exercising leg, suggesting that these ions are extracted from the arterial blood by contracting skeletal muscle.

U2 - 10.1113/jp281995

DO - 10.1113/jp281995

M3 - Article

SN - 0022-3751

VL - 599

SP - 5203

EP - 5214

JO - The Journal of Physiology

JF - The Journal of Physiology

IS - 23

ER -

Nitrate‐rich beetroot juice ingestion reduces skeletal muscle O2 uptake and blood flow during exercise in sedentary men

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Nitrate‐rich beetroot juice ingestion reduces skeletal muscle O₂ uptake and blood flow during exercise in sedentary men