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; FIO ₂ :20.94%) and hypoxia (H; FIO ₂ :13.6%). The participants were divided into two groups matched for age and anthropometric characteristics, but intentionally varying in [Hb] ( p < 0.001) and V̇O _2max ( p < 0.01); iron-deficient (A; n = 8; [Hb]:11.3 ± 0.4 g/dl; V̇O _2max :37.3 ± 2.8 ml/kg/min) and healthy controls (C; n = 8; [Hb]:13.3 ± 0.4 g/dl; V̇O _2max :40.8 ± 1.9 ml/kg/min). Results: During exercise in hypoxia compared to normoxia, the A exhibited greater decrement in V̇O _2max (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 O ₂ utilization under H was observed only in C, based on ΔHHb ( p < 0.05). Cerebral oxygenation was reduced linearly with CaO ₂ ( r = 0.95, p < 0.001). Conclusion: Collectively, moderate hypoxia induced greater reduction of V̇O _2max , 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 ₂ 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.

Article: Arterial blood pressure regulation during prolonged isometric exercise in artistic gymnastic athletes compared to controls - The Journal of Sports Medicine and Physical Fitness 2024 Sep 25 - Minerva Medica - Journals

We examined the effects of carbohydrate ingestion on endurance performance and fatigue during a soccer simulation in adolescent soccer players and evaluated the protocol’s reliability. Nine (13.5 ± 0.4 years pre-PHV) soccer players performed two soccer simulation intermittent exercise sessions on the treadmill (60 min) while consuming 4 boluses of either a CHO or PLC beverage in random, counterbalanced order. Before and immediately after each exercise session, MVC was measured for the quadriceps and the hand. Participants also performed a TTE on a cycle ergometer on three occasions, after each simulation exercise session (CHO and PLC), and on another day in a rested state (CON). The simulation protocol produced an ICC of 0.96 ([0.77–0.98 95%CI], p = 0.01) for VO₂, with 2.24%CV between trials, suggesting strong reliability. TTE was higher (p = 0.01) in the CHO condition (123 ± 33 s) compared to PLC (85 ± 5 s) by 29%. The relative reduction in MVC_LEG was more pronounced in the PLC (22 ± 11%) condition than in CHO (14 ± 6%) (p = 0.05). Compared to the PLC, CHO resulted in lower RPE_local during the second half of the simulation protocol (p < 0.05). Carbohydrate ingestion can improve endurance performance and reduce peripheral fatigue during a reliable soccer simulation that resembles the physiological demands of a youth soccer match.

Background: Temperature regulation is impaired in iron-deficient anemic humans and rats at rest during cold exposure. However, there is a paucity of data regarding the interplay of cold exposure, anemia, and exercise on thermal and cardiovascular responses. Therefore, we aimed to explore thermal and cardiovascular responses of individuals with chronic mild iron-deficiency anemia during exercise in the cold compared to controls. Methods: Nine anemic (5 F, 4 M) and nine control (5 F, 4 M) individuals, matched for body fat, size, and mass but different by design in hematological parameters and physical fitness, participated in the study. The participants cycled in cold 11 °C with 40% relative humidity (RH) and neutral (22 °C, 40% RH) conditions at an intensity ~10% below the respiratory threshold until 1 °C increase in rectal temperature (T_re) or 1 h of exercise, whichever occurred first. Results: In the cold, the anemic individuals showed a lower rate of T_re rise (p = 0.047) and lower mean skin temperature (T_sk) (p = 0.03) compared to controls, while only controls increased heat production compared to the neutral condition (p = 0.035). Moreover, the anemic group exhibited an exaggerated blood pressure response in the cold compared to the neutral environment (p < 0.05), due to heightened total peripheral resistance (p < 0.05) and vasomotor response (p < 0.001). Conclusions: In summary, chronic mild iron-deficiency anemia impaired temperature regulation as judged from the lower rate of T_re rise and an inability to activate further the metabolism at cold. Concomitantly, the anemic participants demonstrated increased cardiovascular strain. This is notable because anemia and these environmental conditions are encountered in the workplace, recreational activities, and athletic endeavors. These findings may inform safety guidelines for athletes, workers, and patients exposed to cold environments.

Background/Objective: Temperature regulation is impaired in iron deficient anemic humans and rats at rest during cold exposure. However, there is a paucity of data regarding the interplay of cold exposure, anemia and exercise on thermal and cardiovascular responses. Therefore, we aimed to explore thermal and cardiovascular responses of individuals with chronic mild iron deficient anemia during exercise in the cold compared to controls. Methods: Nine anemic (5 F, 4 M) and 9 control (5 F, 4 M) individuals, matched for body fat, size, mass but different by design in hematological parameters and physical fitness, participated in the study. The participants cycled in cold (11 °C, 40% RH) and neutral (22 °C, 40% RH) conditions at an intensity ~10% below the respiratory threshold until 1 °C increase in Tre or 1h exercise, whichever occurred first. Results: In the cold, the anemic individuals showed a lower rate of Tre rise compared to controls (p=0.047) and only controls increased heat production (V̇O2) compared to the neutral condition (p=0.035). Moreover, in the cold, the anemic group exhibited lower Tsk than controls (p=0.03) and exaggerated blood pressure response compared to the neutral environment (p<0.05) due to heightened total peripheral resistance (p<0.05) and vasomotor response (p<0.001). Conclusions: In summary, chronic mild iron deficient anemia impaired temperature regulation as judged from the lower rate of Tre rise and an inability to activate further the metabolism at cold. Concomitantly, the anemic participants demonstrated increased cardiovascular strain. This is notable because anemia and these environmental conditions are encountered in the workplace, recreational activities and athletic endeavors.