The Effect of Dietary Nitrate on Nocturnal Sleep-Disordered Breathing and Arterial Oxygen Desaturation at High Altitude

Abstract

Patrician, Alexander, Harald Engan, David Lundsten, Ludger Grote, Helena Vigetun-Haughey, and Erika Schagatay. The effect of dietary nitrate on nocturnal sleep-disordered breathing and arterial oxygen desaturation at high altitude. High Alt Med Biol 19:21-27, 2018.-Sleep-disordered breathing and fluctuations in arterial oxygen saturation (SaO) are common during sleep among lowlanders ascending to high altitude. Dietary nitrate (NO) supplementation has been shown to lower the O consumption in various conditions. Our objective was to investigate whether dietary NO could reduce sleep-disordered breathing and SaO desaturation during sleep at altitude. Cardiorespiratory responses during sleep were measured in 10 healthy lowlanders at 330 m and then again in the Himalayas at 3700-4900 m. Each subject received two 70 mL shots of either beetroot juice (BR; ∼5.0 mmol NO per shot) or placebo (PL: ∼0.003 mmol NO per shot) in a single-blinded, weighted order over two consecutive nights at altitude. At 2.5-4.5 hours into sleep at altitude, BR increased the SaO desaturation drop (4.2 [0.1]% with PL vs. 5.3 [0.4]% with BR; p = 0.024) and decreased the SaO desaturation duration (14.1 [0.9] seconds with PL to 11.1 [0.9] seconds with BR; p = 0.0.041). There was a reduction in breaths with flow limitation (p = 0.025), but no changes in Apnea-Hypopnea Index (AHI), mean and minimum SaO. The study suggests BR supplementation does not improve AHI or oxygenation, but may increase fluctuations in arterial O saturation during sleep at altitude in native lowlanders.

The Noncanonical Pathway for In Vivo Nitric Oxide Generation: The Nitrate-Nitrite-Nitric Oxide Pathway

“…Sleep-disordered breathing is also an occurrence in the acclimatization to hypobaric hypoxia at altitude. Given the reductions in O 2 consumption associated with nitrate supplementation seen at sea level (see earlier), Patrician et al (2018) investigated the acute effects of acute nocturnal dietary nitrate supplementation (10 mmol/day nitrate) in lowlanders after ascent to 3700-4900 m, in comparison with a peri-sea level (300 m) on cardiorespiratory responses during sleep. Acute dietary nitrate supplementation had no effect on various measures of sleep-disordered breathing.…”

Sleep Disorder at High Altitude

“…A single-blind placebocontrolled trial examined the effects of dietary NO 3À supplementation on the degree of sleep-related hypoxemia in healthy subjects at an altitude from 3700 to 4900 m. Each subject received two 70ml shots of either beetroot juice ($5.0mmol NO 3À per shot) or placebo ($0.003mmol NO 3À per shot) over two consecutive nights at altitude. Results of the study favored dietary nitrate in increasing fluctuations in arterial O 2 saturation during sleep at altitude in native lowlanders, but it does not improve AHI or oxygenation [49].…”

Primum non nocere; It’s time to consider altitude training as the medical intervention it actually is!

“…In terms of devices, bi-level positive airway and the addition of dead space via a modified facemask have been shown to positively impact certain aspects of sleep at altitude (Ainslie et al, 2013). Regarding nutrition interventions, Patrician et al (2018) were unable to improve the nocturnal breathing pattern or oxygenation with dietary nitrate supplementation (i.e., beetroot juice), but did demonstrate that the intake of beetroot juice increased the fluctuations in arterial O 2 saturation during sleep at altitude. However, similarly to the field of the pharmacological and device-related countermeasures, further research is needed in the field of nutritional countermeasures as well.…”