Heart Rate Variability Signal Parameters Quantify Skin Cooling Effect of Energy Patches during Rest and Exercise in Young Healthy Individuals

Heart rate variability (HRV) signal analysis provides a non-invasive and sensitive marker of autonomic nervous system (ANS) activity. Spectral parameters of HRV signal are used to quantify the balance between sympathetic and parasympathetic (sympathovagal) influences under various physiologic conditions. ECG signals were acquired, filtered and further processed to derive the HRV signal. The low frequency (LF), high frequency (HF), and their ratio LF/HF were calculated to assess the parasympathetic dominance or the skin cooling effect of a set of non-transdermal Energy Patches on young healthy individuals during Rest and immediately after mild Exercise. HRV data acquired from 20 young healthy volunteers (10 males and 10 females, 19-25 years of age), in a doubleblind placebo-controlled study, were used to evaluate the skin cooling effect of these wearable devices on the ANS during rest and immediately after mild exercise while wearing active (A) and placebo (P) patches. Data from condition (A) and condition (P) were compared using statistical analysis (one-sample inference). The LF/HF decreased significantly both during rest and immediately after mild exercise in condition (A) compared to condition (P) with or p <0.01 with a statistical power of at least 85%. This study shows that the normalized LF/HF derived from spectral analysis of HRV signals could be used to quantify the parasympathetic dominance or the localized skin cooling effect of non-transdermal energy patches during rest and immediately after mild exercise in young healthy individuals.