Dijab Halil, Alastruey Jordi, Charlton Peter H
Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, King's College London, King's Health Partners, St Thomas' Hospital, London SE1 7EH, UK.
Proceedings (MDPI). 2018 Nov 14;4(1):12. doi: 10.3390/ecsa-5-05746.
The rate at which an individual recovers from exercise is known to be indicative of cardiovascular risk. It has been widely shown that the reduction in heart rate immediately after exercise is predictive of mortality. However, little research has been conducted into whether the time taken for the blood vessels to return to normal is also indicative of risk. In this study, we present a novel approach to assess vascular recovery rate (VRR) using the photoplethysmogram (PPG) signal, which is monitored by smart wearables. The VORTAL dataset (http://peterhcharlton.github.io/RRest/) was used for this study, containing PPG signals from 39 healthy subjects before (baseline) and after exercise. 31 VRR indices were extracted from the PPG pulse wave shape, as well as heart rate for comparison. The rate at which indices returned to baseline after exercise was quantified, and the consistency of changes between subjects was assessed statistically. Many VRR indices exhibited changes after exercise which were consistent between subjects. Indices derived from the timings and second derivative of pulse waves were identified as candidates for future work. The rate at which the indices returned to baseline differed between indices and subjects, indicating that they may provide additional information beyond that of heart rate, and that they may be useful for stratifying subjects. This study demonstrated the feasibility of assessing VRR after exercise from the PPG. Future studies should investigate whether VRR indices are associated with cardiovascular fitness, and the potential utility of incorporating the indices into wearable sensors.
众所周知，个体从运动中恢复的速度可表明心血管风险。大量研究表明，运动后心率的立即下降可预测死亡率。然而，关于血管恢复正常所需时间是否也能表明风险，却鲜有研究。在本研究中，我们提出了一种使用光电容积脉搏波描记图（PPG）信号评估血管恢复率（VRR）的新方法，该信号由智能可穿戴设备监测。本研究使用了VORTAL数据集（http://peterhcharlton.github.io/RRest/），其中包含39名健康受试者运动前（基线）和运动后的PPG信号。从PPG脉搏波形中提取了31个VRR指标，并提取了心率用于比较。对运动后指标恢复到基线的速率进行了量化，并对受试者之间变化的一致性进行了统计学评估。许多VRR指标在运动后表现出受试者之间一致的变化。从脉搏波的时间和二阶导数得出的指标被确定为未来研究的候选指标。指标恢复到基线的速率在指标和受试者之间存在差异，这表明它们可能提供超出心率的额外信息，并且可能有助于对受试者进行分层。本研究证明了从PPG评估运动后VRR的可行性。未来的研究应调查VRR指标是否与心血管健康相关，以及将这些指标纳入可穿戴传感器的潜在效用。
