Macro- and microcirculatory factors affecting foot temperature change during walking

Area of Science:

• Physiology
• Exercise Science
• Human Locomotion

Background:

• Skin temperature regulation is complex, influenced by factors like microcirculation and macrocirculation.
• Increased muscle metabolism during walking may elevate foot temperature, but the relationship with macrocirculation (leg blood flow) and microcirculation (tissue saturation index) is not fully understood.

Purpose of the Study:

• To investigate the associations between macrocirculation (leg blood flow), microcirculation (tissue saturation index), and changes in foot temperature during walking on varying slopes.
• To determine how different inclines affect physiological responses related to leg circulation and oxygenation.

Main Methods:

• Healthy young adults (n=21) walked for 10 minutes at 1.2 m/s on 0°, +5°, and -5° slopes in a randomized order.
• Leg blood flow (LBF), tissue saturation index (TSI) at the vastus lateralis (VL), medial gastrocnemius (MG), and dorsal foot, and foot temperature were measured before and after each walking bout.

Main Results:

• Uphill walking significantly increased LBF and reduced TSI in VL and MG, indicating higher muscle oxygen demand.
• Changes in dorsal foot TSI showed a positive association with foot temperature change (β=0.064, P=0.026).
• LBF and TSI in VL and MG were not significantly associated with foot temperature changes (P>0.192).

Conclusions:

• Leg macrocirculation adapts to meet increased metabolic demands of leg muscles during incline walking, independent of foot skin temperature changes.
• Foot temperature regulation during walking appears primarily influenced by factors beyond macrocirculation and muscle microcirculation, such as cutaneous blood flow and heat loss mechanisms.