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Published on: February 16, 2022
Spleen contraction and Hb elevation after dietary nitrate intake
Harald Engan1,2, Alexander Patrician1,3, Angelica Lodin-Sundström1,4
1Environmental Physiology Group, Department of Health Sciences, Mid Sweden University, Östersund, Sweden.
Dietary nitrate supplementation, found in beetroot juice, reduces spleen volume at rest, leading to increased hemoglobin levels. This novel mechanism may enhance oxygen transport and improve performance during exercise, apnea, and hypoxia.
Area of Science:
- Exercise Physiology
- Nutritional Science
- Cardiovascular Physiology
Background:
- Dietary nitrate (NO3-) improves exercise tolerance and reduces exercise oxygen cost.
- Nitrate may attenuate arterial oxygen desaturation during apnea.
- The spleen acts as a dynamic reservoir for red blood cells.
Purpose of the Study:
- To investigate the effect of beetroot juice (BR) rich in nitrate on spleen volume and contraction during apnea.
- To determine the impact of BR on hemoglobin (Hb) concentration.
- To explore a novel mechanism for nitrate's ergogenic effects.
Main Methods:
- Eight volunteers ingested BR or placebo (PL) on separate days.
- Apneas of submaximal and maximal duration were performed.
- Spleen diameters were measured for volume calculation; Hb concentration was analyzed.
Main Results:
- BR ingestion significantly reduced baseline spleen volume (22.9%) and increased Hb concentration (+3.0%).
- Spleen contraction and Hb increase during apnea were similar between BR and PL conditions.
- Dietary nitrate reduced spleen volume at rest, leading to elevated Hb.
Conclusions:
- Dietary nitrate supplementation reduces spleen volume at rest, increasing circulating hemoglobin.
- This spleen-mediated Hb elevation is a novel mechanism potentially contributing to nitrate's ergogenic effects.
- This finding offers new insights into enhancing oxygen transport during physiological stress.
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