Nitrates (beetjuice!) enhance exercise tolerance

[Cort]

The chemistry of this is way beyond me but if ME/CFS patients have problems with aerobic metabolism (O2 consumption) and the nitrates in beet juice reduce the need for O2 consumption during exercise then I wonder if there's something in there for us?

They are talking about mitochondrial respiration and muscle contractile energetics. Maybe someone else can lend a hand with nitrates, oxygen consumption, the mitochondria and muscle activity.

J Appl Physiol. 2009 Aug 6. [Epub ahead of print]
Dietary nitrate supplementation reduces the O2 cost of low-intensity exercise and enhances tolerance to high-intensity exercise in humans.

Pharmacological sodium nitrate supplementation has been reported to reduce the O2 cost of sub-maximal exercise in humans. In this study, we hypothesised that dietary supplementation with inorganic nitrate in the form of beetroot juice (BR) would reduce the O2 cost of sub-maximal exercise and enhance the tolerance to high-intensity exercise. In a double-blind, placebo-controlled, crossover study, eight males (aged 19-38 yr) consumed 500 mL per day of either beetroot juice (BR, containing 11.2 +/- 0.6 mM of nitrate) or blackcurrant cordial (as a placebo, PL, with negligible nitrate content) for six consecutive days, and completed a series of 'step' moderate-intensity and severe-intensity exercise tests on the last 3 days.

High levels of plasma nitrite for apparently good. Systolic blood pressure was reduced, time to exhaustion was increased: they could apparently do more with less by drinking beet juice.

On days 4-6, plasma [nitrite] was significantly greater following dietary nitrate supplementation compared to placebo (BR: 273 +/- 44 vs. PL: 140 +/- 50 nM; P<0.05) and systolic blood pressure was significantly reduced (BR: 124 +/- 2 vs. PL: 132 +/- 5 mmHg; P<0.01). During moderate exercise, nitrate supplementation reduced muscle fractional O2 extraction (as estimated using near infra-red spectroscopy). The gain of the increase in pulmonary VO2 following the onset of moderate exercise was reduced by 19% in the BR condition (BR: 8.6 +/- 0.7 vs. PL: 10.8 +/- 1.6 mL(.)min(-1)(.)W(-1); P<0.05). During severe exercise, the VO2 slow component was reduced (BR: 0.57 +/- 0.20 vs. PL: 0.74 +/- 0.24 L.min(-1); P<0.05) and the time-to-exhaustion was extended (BR: 675 +/- 203 vs. PL: 583 +/- 145 s; P<0.05).

The reduced O2 cost of exercise following increased dietary nitrate intake has important implications for our understanding of the factors which regulate mitochondrial respiration and muscle contractile energetics in humans. Key words: VO2 kinetics, exercise tolerance, exercise economy, slow component.

Here are the authors

Corresponding author of the study, Professor Andy Jones of the University of Exeter's School of Sport and Health Sciences, said: "Our study is the first to show that nitrate-rich food can increase exercise endurance. We were amazed by the effects of beetroot juice on oxygen uptake because these effects cannot be achieved by any other known means, including training. I am sure professional and amateur athletes will be interested in the results of this research. I am also keen to explore the relevance of the findings to those people who suffer from poor fitness and may be able to use dietary supplements to help them go about their daily lives."

BUT, BUT, BUT, BUT At the recent Reno conference Suarez from Spain found.......guess what INCREASED NITRATES in ME/CFS patients

This was just a single exercise test but that’s all it took; these 37 consecutive chronic fatigue syndrome (ME/CFS) patients blew their healthy counterparts away with higher (much higher) nitrate levels in their blood (but not lactate or glucose) levels after a single exercise test.

This was definitely new. Several studies have looked for abnormal lactate levels – a common finding in muscle dysfunction - but their findings have been inconsistent. But now nitrates show up – in spades - in ME/CFS patient’s blood. Not only that but it’s a very strange finding.

Nitrate in the blood is derived from nitric oxide (NO) which the endothelial cells lining our blood vessels produce in order to increase the size of the blood vessels (and increase blood flows). These findings then appear to suggest that these patient’s blood vessels were too open. Usually in disease it’s just the opposite they’re too narrowed.

Nitrates are often given to heart patients in order to increase blood vessel dilation and improve blood flows to the heart. They are used to increase exercise capacity! but here we have these exercise impaired patients with higher than normal nitrate levels!

Interestingly in Italo Biaggoni’s NIH funded study he is looking for signs of the opposite situation - decreased endothelial nitric oxide production. It’s hard to know what to make of this little study. Will it simply be another odd blip on the ME/CFS radar or will it amount to something? Only time will tell.

God knows what's going on....