Related Experiment Video
Updated: May 17, 2026

Preparation of Rat Skeletal Muscle Homogenates for Nitrate and Nitrite Measurements
Published on: July 29, 2021
Effects of dietary inorganic nitrate on static and dynamic breath-holding in humans
Tomas A Schiffer1, Filip J Larsen, Jon O Lundberg
1Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden. tomas.schiffer@ki.se
Abstract:
Inorganic nitrate has been shown to reduce oxygen cost during exercise. Since the nitrate-nitrite-NO pathway is facilitated during hypoxia, we investigated the effects of dietary nitrate on oxygen consumption and cardiovascular responses during apnea. These variables were measured in two randomized, double-blind, placebo-controlled, crossover protocols at rest and ergometer exercise in competitive breath-hold divers. Subjects held their breath for predetermined times along with maximum effort apneas after two separate 3-day periods with supplementation of potassium nitrate/placebo. In contrast to our hypothesis, nitrate supplementation led to lower arterial oxygen saturation (SaO(2), 77 ± 3%) compared to placebo (80 ± 2%) during static apnea, along with lower end-tidal fraction of oxygen (FETO(2)) after 4 min of apnea (nitrate 6.9 ± 0.4% vs. placebo 7.6 ± 0.4%). Maximum apnea duration was shorter after nitrate (329 ± 13 s) compared to placebo (344 ± 13 s). During cycle ergometry nitrate had no effect on SaO(2), FETO(2) or maximum apnea duration. The negative effects of inorganic nitrate during static apnea may be explained by an attenuated diving response.
More Related Videos
Related Concept Videos
Inorganic Nitrogen Assimilation
2° Amines to N-Nitrosamines: Reaction with NaNO2
Hyperpnea and Hyperventilation
Physiological Control of Respiration
Breathing, a seemingly passive process, is regulated by the respiratory center in the brainstem. This center coordinates the involuntary control of respirations, which means it occurs without conscious effort, ensuring a smooth and uninterrupted pattern.
Regulation of Ventilation
The body maintains ventilation by monitoring levels of carbon dioxide (CO2), oxygen (O2), and hydrogen ion concentration (pH) in the arterial blood. Among these factors, the level of CO2 plays a crucial...
Chemical Factors Affecting Respiration Centers
CO2 has a potent influence on respiration and is strictly regulated. Under...

