Cardiovascular and Thermal Responses to Cold Exposure During Exercise in Iron-Deficient Anemic Individuals

Area of Science:

• Exercise physiology
• Environmental medicine
• Hematology

Background:

• Impaired temperature regulation in iron-deficient anemic individuals during cold exposure at rest.
• Limited data on combined effects of cold, anemia, and exercise on physiological responses.
• Need to investigate thermal and cardiovascular adjustments during exercise in the cold for anemic individuals.

Purpose of the Study:

• To explore thermal and cardiovascular responses in chronic mild iron-deficiency anemia during cold-weather exercise.
• To compare responses of anemic individuals with healthy controls under cold and neutral conditions.
• To assess the impact of iron-deficiency anemia on thermoregulation and cardiovascular strain during physical exertion in the cold.

Main Methods:

• Nine anemic and nine control participants (matched for body composition) underwent cycling exercise.
• Exercise performed in cold (11 °C) and neutral (22 °C) conditions at ~10% below respiratory threshold.
• Study endpoint: 1 °C increase in rectal temperature (T_re) or 1 hour of exercise.

Main Results:

• Anemic individuals exhibited a lower rate of T_re rise and reduced mean skin temperature (T_sk) in the cold.
• Only controls increased heat production in the cold compared to neutral conditions.
• Anemic group showed exaggerated blood pressure response in the cold due to increased total peripheral resistance and vasomotor activity.

Conclusions:

• Chronic mild iron-deficiency anemia impairs thermoregulation, evidenced by reduced T_re rise and blunted metabolic heat production in the cold.
• Anemic individuals experience increased cardiovascular strain during cold-weather exercise.
• Findings are relevant for safety guidelines in occupational, recreational, and athletic settings involving cold exposure for anemic individuals.