Skin Blood Flow Suffers Despite Heat and Cold Cycles During Long Sitting

Prolonged sitting, averaging about 7 hours daily in Japan—the highest globally, increases the risk of cardiovascular issues. A team from USC recently discovered that sitting for extended periods under stable skin temperature conditions can reduce the skin’s ability to dilate blood vessels, while alternating between local heating and cooling may help lessen this effect (1^✔ ✔Trusted Source
Sustained sitting attenuates cutaneous reactive hyperemia while improving venoarteriolar reflex, and alternating ambient exposure to cool and heat does not modulate these responses

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Prolonged Sitting and Skin Temperature Effects

In Japan, people spend approximately 7h sitting per day, which is the longest sitting time in the world. This sedentary behavior (i.e., repeated bouts of prolonged sitting) increases the risk of cardiovascular disease. Recently, a research group has reported that prolonged sitting under constant skin temperature conditions can impair cutaneous vasodilation function, and repeated local heating and cooling can mitigate this impairment.

Simulated Environmental Conditions and Participant Setup

In this study, researchers investigated the effects of prolonged sitting on forearm cutaneous vascular function under two conditions simulating real-life environments: Constant room temperature and alternating cooling and heating ambient temperatures. A total of 12 young adults (six women) were included in this study.

The participants sat for 120 min under the alternating temperature condition, during which they were exposed to 18°C followed by 35°C, with this sequence repeated twice. On a separate day, they were exposed to a thermoneutral ambient temperature of 25°C for 120 min under the constant temperature condition. Cutaneous vascular function was assessed and compared between the two conditions.

Vascular Function Outcomes and Temperature Exposure

The results showed that prolonged sitting decreased cutaneous vasodilation function but enhanced vasoconstrictor responsiveness. Alternating exposure to cooling and heating did not significantly suppress these changes in cutaneous vascular function.

These findings indicate that temperature stimulation of the surrounding environment cannot prevent the vascular dysfunction caused by prolonged sitting. Therefore, developing more effective interventions, including those that elicit greater local skin temperature fluctuations, is crucial.

Reference:

1. Sustained sitting attenuates cutaneous reactive hyperemia while improving venoarteriolar reflex, and alternating ambient exposure to cool and heat does not modulate these responses - (https://link.springer.com/article/10.1007/s00421-025-05870-7)

Source-Eurekalert