Effects of intermittent pinpoint thermal stimulation using electronic moxibustion on cardiovascular responses: a randomized crossover study

Abstract Background Moxibustion is a traditional therapeutic modality in which localized, pinpoint thermal stimulation is applied to specific cutaneous sites (acupoints). Although used for cardiovascular conditions, the physiological responses to such spatially restricted thermal stimulation remain insufficiently understood, particularly in comparison with large-area heating that delivers broader thermal input. In particular, it remains unclear whether the temporal pattern of stimulation influences sustained cardiovascular responses, which is important for the development of effective stimulation protocols and potential clinical application. The present study examined the effects of pinpoint thermal stimulation, mimicking moxibustion, on cardiovascular responses using a two-stage design. Methods Twenty-nine healthy students participated in this study. Study 1 (n = 14) consisted of a 3-min baseline period (Pre) followed by 3 min of continuous thermal stimulation (Stim). Study 2 (n = 15) used a randomized crossover design with control (CL) and intermittent thermal stimulation (TL) conditions, each including a 5-min Pre and a 5-min intervention period (Stim). Thermal stimulation was applied to the Zusanli acupoint (ST36) using an electronic moxibustion device with a ceramic 2-mm tip. Heart rate (HR), mean blood pressure (MBP), and skin temperature (SKT) were continuously recorded. Heart rate variability (HRV) indices were analyzed in Study 2. Data were analyzed using one-way or two-way repeated-measures ANOVA. Results In Study 1, HR decreased during stimulation associated with increased SKT, but returned toward baseline during continuous stimulation (p < 0.001). In Study 2, HR decreased during Stim in the TL condition accompanied by increased SKT, and was maintained throughout the intervention period. Significant Condition × Time interactions were observed for HR (p = 0.001), SKT (p < 0.001), high-frequency power in normalized units (HFnu) (p = 0.019), and low frequency/high frequency (LF/HF) ratio (p = 0.002). No significant interaction was observed for MBP. Conclusion Pinpoint thermal stimulation reduced HR associated with increase in local SKT. This response was transient during continuous stimulation but was sustained during intermittent stimulation, indicating that the temporal pattern of stimulation influences the persistence of cardiovascular effects. This study provides a physiological basis for and may support the development of clinical application of pinpoint thermal stimulation. Trial registration The University Hospital Medical Information Network Clinical Trials Registry, UMIN000062912, Date: 2026-9-15, Retrospectively registered.