## 3 Results
### Hypoxia Exercise Test Performance  
Acute HET significantly decreased the SpO\({}_{2}\), blood pH value, and PCO\({}_{2}\) and increased the blood lactate concentration, erythrocyte count, hemoglobin, hematocrit, and EPO. Both NE and HE for 6 weeks significantly diminished the exercise-related augmentation of the HR, pH value, and Lac concentration, which indicated improved anti-hypoxic stress capacity under the same hypoxic challenge. No alterations in the erythrocyte count, hemoglobin level, or hematocrit were found in NE or HE, whereas EPO was significantly augmented after HE (Table 2).  
\begin{table}
\begin{tabular}{l c c c c c c} \hline \hline  & \multicolumn{2}{c}{**NE**} & \multicolumn{2}{c}{**HE**} & \multicolumn{2}{c}{**CTL**} \\  & **Pretraining** & **Post-Training** & **Pretraining** & **Post-Training** & **Pretraining** & **Post-Training** \\ \hline
**Anthropometric variables** & & & & & & \\ \hline Age (years) & 22.4 \(\pm\) 0.9 & — & 21.9 \(\pm\) 0.7 & — & 23.1 \(\pm\) 0.9 & — \\ Height (cm) & 173 \(\pm\) 2 & — & 173 \(\pm\) 3 & — & 174 \(\pm\) 2 & — \\ Weight (kg) & 68.1 \(\pm\) 2.2 & 66.9 \(\pm\) 3.1 & 66.9 \(\pm\) 2.5 & 66.7 \(\pm\) 2.3 & 65.7 \(\pm\) 2.3 & 66.2 \(\pm\) 1.8 \\
**Ventilation threshold performance** & & & & & \\ \hline Work Rate (watt) & 121 \(\pm\) 7 & 155 \(\pm\) 7 * & 123 \(\pm\) 4 & 156 \(\pm\) 4 * & 122 \(\pm\) 5 & 124 \(\pm\) 4 \\ V\({}_{\rm E}\) (L min\({}^{-1}\)) & 55.5 \(\pm\) 3.6 & 72.0 \(\pm\) 4.6 * & 55.8 \(\pm\) 4.5 & 70.4 \(\pm\) 4.3 * & 55.6 \(\pm\) 4.1 & 56.3 \(\pm\) 4.2 \\ VO\({}_{2}\) (mL kg\({}^{-1}\) min\({}^{-1}\)) & 23.7 \(\pm\) 1.3 & 30.0 \(\pm\) 1.8 * & 23.9 \(\pm\) 1.7 & 28.2 \(\pm\) 1.3 * & 23.4 \(\pm\) 1.6 & 23.2 \(\pm\) 1.5 \\ HR (bpm) & 149 \(\pm\) 3 & 157 \(\pm\) 3 * & 147 \(\pm\) 4 & 153 \(\pm\) 3 & 147 \(\pm\) 4 & 149 \(\pm\) 3 \\ CO (L min\({}^{-1}\)) & 14.3 \(\pm\) 0.6 & 15.1 \(\pm\) 0.6 & 14.4 \(\pm\) 0.5 & 15.6 \(\pm\) 0.8 & 14.1 \(\pm\) 0.4 & 14.4 \(\pm\) 0.6 \\ MAP (mmHg) & 119 \(\pm\) 2 & 123 \(\pm\) 3 & 117 \(\pm\) 2 & 118 \(\pm\) 2 & 116 \(\pm\) 3 & 115 \(\pm\) 2 \\
**Peak performance** & & & & & & \\ \hline Work Rate (watt) & 187 \(\pm\) 5 & 216 \(\pm\) 5 * & 189 \(\pm\) 5 & 228 \(\pm\) *,* & 188 \(\pm\) 5 & 189 \(\pm\) 5 \\ V\({}_{\rm E}\) (L min\({}^{-1}\)) & 117.9 \(\pm\) 3.4 & 124.4 \(\pm\) 3.9 * & 117.7 \(\pm\) 4.8 & 137.9 \(\pm\) 3.6 *,* & 116.86 \(\pm\) 3.9 & 117.9 \(\pm\) 3.1 \\ VO\({}_{2}\) (ml kg\({}^{-1}\) min\({}^{-1}\)) & 33.6 \(\pm\) 1.1 & 36.3 \(\pm\) 1.1 * & 33.4 \(\pm\) 1.4 & 38.8 \(\pm\) 1.3 *,* & 33.8 \(\pm\) 1.3 & 32.2 \(\pm\) 1.1 \\ HR (bpm) & 195 \(\pm\) 2 & 193 \(\pm\) 2 & 193 \(\pm\) 2 & 193 \(\pm\) 2 & 193 \(\pm\) 2 & 193 \(\pm\) 2 & 194 \(\pm\) 3 \\ CO (L min\({}^{-1}\)) & 16.0 \(\pm\) 0.5 & 16.3 \(\pm\) 0.4 & 16.3 \(\pm\) 0.6 & 18 \(\pm\) 0.5 * & 16.2 \(\pm\) 0.4 & 15.9 \(\pm\) 0.5 \\ MAP (mmHg) & 128 \(\pm\) 2 & 133 \(\pm\) 3 & 129 \(\pm\) 2 & 132 \(\pm\) 2 & 129 \(\pm\) 2 & 128 \(\pm\) 3 \\ \hline \hline \end{tabular} Values are mean \(\pm\) SEM. V\({}_{\rm E}\), minute ventilation; VO\({}_{2}\), oxygen consumption; HR, heart rate; CO, cardiac output; MAP, mean arterial pressure; NE, normoxia training group; HE, hypoxia training group; CTL, control group. * \(p\) < 0.05, Pre vs. Post; * \(p\) < 0.05, NE vs. HE.  
\end{table}
Table 2: Effects of NE and HE on erythrocyte characteristics and serum erythropoietin concentration in HET (hypoxia).  
\begin{table}
\begin{tabular}{l c c c c c c} \hline \hline  & & **NE** & **HE** & **CTL** \\  & **Pretraining** & **Post-Training** & **Pretraining** & **Post-Training** & **Pretraining** & **Post-Training** \\ \hline HR (bpm) & & & & & & \\  & **Rt** & 77 \(\pm\) 3 & 81 \(\pm\) 5 & 80 \(\pm\) 2 & 78 \(\pm\) 3 & 77 \(\pm\) 2 & 78 \(\pm\) 4 \\  & Ex & 154 \(\pm\) 2 * & 142 \(\pm\) 5 *,* & 156 \(\pm\) 3 * & 141 \(\pm\) 2 *,* & 153 \(\pm\) 3 * & 151 \(\pm\) 3 * \\ SpO\({}_{2}\) (\%) & & & & & & \\  & **Rt** & 94 \(\pm