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Purpose <p>Integrated physiological responses during maximal whole-body exercise, such as cycling, under additive hypoxemia (anemia + hypoxia) are not adequately studied. Therefore, we investigated cardiovascular, muscular and cerebral oxygenation responses in chronic mildly iron-deficient and control women under normoxic and moderate hypoxic conditions during maximal whole-body exercise.</p> Methods <p>In a randomized and counterbalanced order, 16 females performed incremental exercise to exhaustion under normoxia (N; FIO<sub>2</sub>:20.94%) and hypoxia (H; FIO<sub>2</sub>:13.6%). The participants were divided into two groups matched for age and anthropometric characteristics, but intentionally varying in [Hb] (<i>p</i> &lt; 0.001) and V̇O<sub>2max</sub> (<i>p</i> &lt; 0.01); iron-deficient (A; <i>n</i> = 8; [Hb]:11.3 ± 0.4&#xa0;g/dl; V̇O<sub>2max</sub>:37.3 ± 2.8&#xa0;ml/kg/min) and healthy controls (C; <i>n</i> = 8; [Hb]:13.3 ± 0.4&#xa0;g/dl; V̇O<sub>2max</sub>:40.8 ± 1.9&#xa0;ml/kg/min).</p> Results <p>During exercise in hypoxia compared to normoxia, the A exhibited greater decrement in V̇O<sub>2max</sub> (5.0%; <i>p</i> = 0.02) and peak power output (5.4%; <i>p</i> = 0.004) than C. Maximal mean arterial pressure was reduced (<i>p</i> &lt; 0.05) due to lower total peripheral resistance (<i>p</i> &lt; 0.05) and unchanged maximal cardiac output (<i>p</i> &gt; 0.05). Enhanced O<sub>2</sub> utilization under H was observed only in C, based on ΔHHb (<i>p</i> &lt; 0.05). Cerebral oxygenation was reduced linearly with CaO<sub>2</sub> (<i>r</i> = 0.95, <i>p</i> &lt; 0.001).</p> Conclusion <p>Collectively, moderate hypoxia induced greater reduction of V̇O<sub>2max</sub>, peak power output and cerebral oxygenation leading to exercise intolerance in A compared to C. These responses were accompanied by an inability of skeletal muscle to increase O<sub>2</sub> utilization at maximal effort in H and by a failure of the cardiovascular system to compensate and counteract convective and diffusion limitations during maximal whole-body exercise in anemic women.</p>

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Cardiorespiratory and oxygenation responses in iron-deficient anemic women during whole-body exercise under moderate hypoxia

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年9月1日

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  • Panagiotis G. Miliotis,
  • Spyridoula D. Ntalapera,
  • Panagiotis Lakeas,
  • Ioannis Loukas,
  • Argyris G. Toubekis,
  • Nickos D. Geladas,
  • Maria D. Koskolou

摘要

Purpose

Integrated physiological responses during maximal whole-body exercise, such as cycling, under additive hypoxemia (anemia + hypoxia) are not adequately studied. Therefore, we investigated cardiovascular, muscular and cerebral oxygenation responses in chronic mildly iron-deficient and control women under normoxic and moderate hypoxic conditions during maximal whole-body exercise.

Methods

In a randomized and counterbalanced order, 16 females performed incremental exercise to exhaustion under normoxia (N; FIO2:20.94%) and hypoxia (H; FIO2:13.6%). The participants were divided into two groups matched for age and anthropometric characteristics, but intentionally varying in [Hb] (p < 0.001) and V̇O2max (p < 0.01); iron-deficient (A; n = 8; [Hb]:11.3 ± 0.4 g/dl; V̇O2max:37.3 ± 2.8 ml/kg/min) and healthy controls (C; n = 8; [Hb]:13.3 ± 0.4 g/dl; V̇O2max:40.8 ± 1.9 ml/kg/min).

Results

During exercise in hypoxia compared to normoxia, the A exhibited greater decrement in V̇O2max (5.0%; p = 0.02) and peak power output (5.4%; p = 0.004) than C. Maximal mean arterial pressure was reduced (p < 0.05) due to lower total peripheral resistance (p < 0.05) and unchanged maximal cardiac output (p > 0.05). Enhanced O2 utilization under H was observed only in C, based on ΔHHb (p < 0.05). Cerebral oxygenation was reduced linearly with CaO2 (r = 0.95, p < 0.001).

Conclusion

Collectively, moderate hypoxia induced greater reduction of V̇O2max, peak power output and cerebral oxygenation leading to exercise intolerance in A compared to C. These responses were accompanied by an inability of skeletal muscle to increase O2 utilization at maximal effort in H and by a failure of the cardiovascular system to compensate and counteract convective and diffusion limitations during maximal whole-body exercise in anemic women.