## 4 Discussion
### Methodological Considerations--Nitrate Dosage, Oxygen Uptake, and Measurements  
The total amount of NO\({}_{3}\)\({}^{-}\) given to the participants in the present study (0.14 mmol NO\({}_{3}\)\({}^{-}\)/kg body weight/day) was similar to that reported in other studies [13]. Recently, experts have recommended an acute bolus of 5-9 mmol [44] or 8-16 mmol NO\({}_{3}\)\({}^{-}\)[45] to be taken 2-4 h before exercise. The dose of NaNO\({}_{3}\) used in this study is within the \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Time** & **Group** & **FFA (mM)** & **Glyc (mM)** & **TG (mM)** \\ \hline \multirow{2}{*}{Baseline WT 1  } & N & 0.29 \(\pm\) 0.33 & 0.09 \(\pm\) 0.09 & 1.10 \(\pm\) 0.48 \\  & P & 0.33 \(\pm\) 0.28 & 0.08 \(\pm\) 0.04 & 1.23 \(\pm\) 0.78 \\ \hline \multirow{2}{*}{Baseline ECT 1  } & N & 0.29 \(\pm\) 0.30 & 0.05 \(\pm\) 0.04 & 1.14 \(\pm\) 0.52 \\  & P & 0.23 \(\pm\) 0.15 & 0.05 \(\pm\) 0.02 & 0.99 \(\pm\) 0.61 \\ \hline \multirow{2}{*}{Rest} & N & 0.19 \(\pm\) 0.16 & 0.06 \(\pm\) 0.02 & 0.77 \(\pm\) 0.30 * \\  & P & 0.27 \(\pm\) 0.19 & 0.07 \(\pm\) 0.03 & 1.32 \(\pm\) 0.59 \\ \hline \multirow{2}{*}{5 th interval} & N & 0.15 \(\pm\) 0.06 & 0.08 \(\pm\) 0.03 & 0.78 \(\pm\) 0.35 \\  & P & 0.18 \(\pm\) 0.13 & 0.08 \(\pm\) 0.02 & 1.49 \(\pm\) 0.64 \\ \hline \multirow{2}{*}{20 th interval} & N & 0.16 \(\pm\) 0.05 & 0.09 \(\pm\) 0.02 & 0.83 \(\pm\) 0.28 * \\  & P & 0.20 \(\pm\) 0.15 & 0.10 \(\pm\) 0.02 & 1.32 \(\pm\) 0.65 \\ \hline \multirow{2}{*}{35 th interval} & N & 0.18 \(\pm\) 0.05 & 0.11 \(\pm\) 0.04 & 0.74 \(\pm\) 0.26 * \\  & P & 0.20 \(\pm\) 0.13 & 0.12 \(\pm\) 0.03 & 1.47 \(\pm\) 0.65 \\ \hline \multirow{2}{*}{45 th interval} & N & 0.20 \(\pm\) 0.08 & 0.13 \(\pm\) 0.06 & 0.70 \(\pm\) 0.21 * \\  & P & 0.24 \(\pm\) 0.17 & 0.14 \(\pm\) 0.05 & 1.49 \(\pm\) 0.76 \\ \hline \multirow{2}{*}{Cool-down} & N & 0.23 \(\pm\) 0.10 & 0.14 \(\pm\) 0.07 & 0.69 \(\pm\) 0.21 * \\  & P & 0.26 \(\pm\) 0.17 & 0.17 \(\pm\) 0.05 & 1.32 \(\pm\) 0.67 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Summary of the plasma concentrations of free fatty acids, free glycerol, and triglycerides in the N and P groups at the indicated time points in the training test. recommended range [44; 45]. Even at lower doses, some authors have observed acute effects of NO3\({}^{-}\) on VO2 during submaximal exercise [16; 17; 20]. No such effects were observed in the present study. These differences may be, at least in part, due to the use of different types of nitrate supplementation, for example as an aqueous solution of pure chemical NaNO3 (present study) or as BRJ (in other studies) [46]. This is noteworthy because BRJ may contain antioxidants, including polyphenols, which are known to increase NO2\({}^{-}\) reduction to NO in the gut and the brain [46; 47]. In addition, other not yet known components of BRJ may exert additional NO independent effects on physical performance. In a meta-analysis, both supplementation induced similar effects on VO2 during moderate (<60%VO2 peak) and heavy (60-80%VO2 peak) intensity exercise [6]. However, the number of studies included in this meta-analysis is relatively small and the result may be biased. Recent studies have found that NO3\({}^{-}\) can be stored not only in the blood but also in the skeletal muscle [48; 49; 50; 51]. This NO3\({}^{-}\) reservoir plays an important role during intense or prolonged exercise. In the present study, the concentration of NO3\({}^{-}\) and NO2\({}^{-}\) was measured only in plasma. Therefore, it is not possible to differentiate between the effects of NO3\({}^{-}\) stored in the skeletal muscle or blood. [PERSON] et al. [52] showed that the decrease in VO2 at moderate intensity due to nitrate supplementation is negatively correlated with VO2 peak. Highly trained individuals (VO2 peak \(\geq\) 60 mL/kg/min) may not experience ergogenic effects from inorganic nitrate supplementation [52]. Studies on elite athletes have supported these findings [53; 54; 55].