Muscle oxygenation profiles between active and inactive muscles with nitrate supplementation under hypoxic exercise
| Autor: | Yoko Handa, Junko Endo, Katsuhiro Koyama, Masataka Kiuchi, Shohei Dobashi, Masahiro Horiuchi |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Adult
Male medicine.medical_specialty Skeletal Muscle Physiology chemistry.chemical_element 030204 cardiovascular system & hematology Beetroot Juice Oxygen muscle O2 extraction Muscle Metabolism 03 medical and health sciences 0302 clinical medicine Oxygen Consumption Physiology (medical) Internal medicine Heart rate medicine Deoxygenated Hemoglobin tissue oxygenation Humans Hypoxia Muscle Skeletal Exercise Oxygen saturation (medicine) Original Research Exercise Tolerance Nitrates Chemistry Endurance and Performance Microcirculation Skeletal muscle 030229 sport sciences Oxygenation Blood flow Hypoxia (medical) Surgery sympathetic vasoconstriction Endocrinology medicine.anatomical_structure Gastrointestinal Hepatic and Pancreatic Physiology Dietary Supplements medicine.symptom Beta vulgaris |
| Zdroj: | Physiological Reports |
| ISSN: | 2051-817X |
| Popis: | Whether dietary nitrate supplementation improves exercise performance or not is still controversial. While redistribution of sufficient oxygen from inactive to active muscles is essential for optimal exercise performance, no study investigated the effects of nitrate supplementation on muscle oxygenation profiles between active and inactive muscles. Nine healthy males performed 25 min of submaximal (heart rate ~140 bpm; EX sub ) and incremental cycling (EX max ) until exhaustion under three conditions: (A) normoxia without drink; (B) hypoxia (FiO 2 = 13.95%) with placebo (PL); and (c) hypoxia with beetroot juice (BR). PL and BR were provided for 4 days. Oxygenated and deoxygenated hemoglobin (HbO 2 and HHb) were measured in vastus lateralis (active) and biceps brachii (inactive) muscles, and the oxygen saturation of skeletal muscle (StO 2 ; HbO 2 /total Hb) were calculated. During EX sub , BR suppressed the HHb increases in active muscles during the last 5 min of exercise. During EX max , time to exhaustion with BR (513 ± 24 sec) was significantly longer than with PL (490 ± 39 sec, P 0.05). In active muscles, BR suppressed the HHb increases at moderate work rates during EX max compared to PL ( P 0.05). In addition, BR supplementation was associated with greater reductions in HbO 2 and StO 2 at higher work rates in inactive muscles during EX max . Collectively, these findings indicate that short‐term dietary nitrate supplementation improved hypoxic exercise tolerance, perhaps, due to suppressed increases in HHb in active muscles at moderate work rates. Moreover, nitrate supplementation caused greater reductions in oxygenation in inactive muscle at higher work rates during hypoxic exercise. |
| Databáze: | OpenAIRE |
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