Unived Elite Beet-420

• Once ingested, the nitrate (NO3–) is reduced to nitrite (NO2–), by anaerobic bacteria in the oral cavity by the action of nitrate reductase enzymes and then to nitric oxide (NO) in the stomach. This physiological mechanism depends on the entero-salivary circulation of inorganic nitrate without involving NOS activityi.  
• Once in the acidic stomach, nitrite is instantly decomposed to convert to NO and other nitrogen oxides performing determinant physiological functions. Nitrate and remaining nitrite is absorbed from the intestine into the circulation, which can become bioactive NO in tissues and blood under physiological hypoxia1. 
• NO induces several physiological mechanisms that influence O2 utilization during contraction skeletal muscle. Physiological mechanisms for NO2– reduction are facilitated by hypoxic conditions; therefore, NO (vasodilator) is produced in those parts of muscle that are consuming or in need of more O2. This mechanism would allow local blood flow to adapt to O2 requirement, providing within skeletal muscle an adequate homogeneous distribution. This physiological response could be positive in terms of muscle function during exercise improving performance1. 

• Nitric oxide, being a major vasodialator that can increase blood flow to muscles and promote oxygen transfer in the muscle. Additional physiological benefits of NO include improved mitochondrial efficiency and glucose uptake in muscle and enhanced muscle contraction and relaxation processes1. 
• It is known that NO has an important role in the adaptation processes under hypoxic conditions, the vasodilatory effects of NO may favor oxygen delivery, and supplementation with beetroot juice could be effective in reducing the ergolytic effects of hypoxia on cardiorespiratory endurance1. 

• A study in trained cyclists found that beetroot juice supplementation improves performance by 0.8% in a 50-mile test. These findings suggests that beetroot juice might have an ergogenic effect, increasing performance in prolonged cycling events that require alternations in relative intensity, from moderate to high VO2max, which is very characteristic of the stages of cycling racesiii. 

• NO3 – supplementation increased the capacity for muscle diffusive O2 transport across active muscle sites, as reflected by higher end-exercise deoxy [Hb + Mb] and total [Hb + Mb], which correlated with a lower VO2Sc amplitude. These helps understand the mechanisms by which short-term NO3– supplementation can improve efficiency during continuous submaximal exercise3. 
• It appears that acute supplementation with beetroot juice increases the power output with the same VO2 levels. This is an interesting finding for athletes as there is evidence that the economy is a key factor to improve cardio-respiratory performance increasing energy efficiency in endurance sports modalities. Time to exhaustion at several intensities (60%–100% VO2max, MAP or VT1) is another usual performance parameter that is improved with acute beetroot supplementation1. 
• During the 2-h moderate-intensity exercise bout, plasma [NO2–] declined by ~17% in BR +PL but increased by ~8% in BR+BR such that, at 2 h, plasma [NO2–] was greater in BR+BR than both BR+PL and PL+PL (P<0.05)iv.  

VO2 was not different among conditions over the first 90 min of exercise but was lower at 120 min in study group compared to placebo4.  

The decline in muscle glycogen concentration over the 2-h exercise bout was attenuated in study group (~28% decline) compared with placebo (~44% decline)4. 

Thus, beetroot supplementation before and during prolonged moderate-intensity exercise attenuated the progressive rise in VO2 over time and appeared to reduce muscle glycogen depletion4.