Heart rate variability features for different stress classification

Abstract

AIM: Autonomic nervous system (ANS) activities during different types of stress could affect the electrocardiogram (ECG) signal. This study aimed to recognize the types of stress by using different ECG signals in order to prevent its actual physiological effects on the heart signal. METHOD: The ECG signal recorded by portable wrist bracelets from 20 students in during seven phases which incorporated three different types of stress and four relaxation phases. After different forms of windowing the signal, we used linear and non-linear features such as detrended fl uctuation analysis (DFA), Poincaré plot, approximate and sample entropy, correlation dimension, and recurrence plot to extract various features of the heart rate variability (HRV). Then, different classifi ers were used to identify the types of stress. RESULTS: The results showed a decrease in NN50, RMSSD, pNN50, and recurrence plot features, and an increase in the DFA method during stress stages, which show the effect of stress on heart rate. Also, by using the convolutional neural network (CNN), an average classifi cation rate of 98 % was obtained in association with cognitive stress and that of 94.5 % in association with emotional stress. CONCLUSION: This paper showed that features extracted from HRV can detect the stress and non-stress stages with high signifi cance. Also, the accuracy of this paper proved that the proposed method is successful in preventing the dangerous effects of different types of stress on the heart (Tab.

Efficient methods for acute stress detection using heart rate variability data from Ambient Assisted Living sensors

“…There are numerous different methods reported in the stress detection literature for inducing stress. These include different arithmetic tasks [20,26,28,29,34], games/puzzles [25,30], exam-like conditions [14,16,19,31], and everyday situations such as driving [38,39] or work shifts [9,10,33]. However, not all of these are standardised and reliable stressors, only ad hoc methods designed and implemented by the researchers themselves, often without psychological expertise.…”

“…In comparison with the results of Ham et al [23], who have achieved 81-82% accuracy with non-overlapping 4-min-long time windows, we have achieved an accuracy of 86.67%, which could be increased to 94.60% by using overlapping time windows of the same length. Moridani et al [20] reported an F1 score of 97.9% for differentiating between cognitive stress and relaxation using 5-min-long measurements. Our results for overlapping 5-min-long time windows using time-domain and non-linear HRV features were quite similar, with an F1 score of 96.26%.…”

“…Some of these solutions work by using just one selected sensor type, while others simultaneously record data from multiple sources. Singlesensor-based solutions often use electrocardiogram (ECG) [13][14][15][16][17][18][19][20][21][22] or photoplethysmogram (PPG) [23][24][25][26] signals, usually to obtain heart rate variability (HRV) features. In other cases, electrodermal activity (EDA) [27] or electromagnetic waves ("bioradar") [28] are used.…”

“…The focus of the research is shifting to developing methods that utilise compact, inexpensive wearable sensor devices suitable for everyday use for both approaches. Such devices are chest belts [13,22,33] or ECG-infused clothing [19], wrist bracelets or activity trackers [9,10,20,27], or other portable ECG devices [13,21]. Unfortunately, these are not yet without some drawbacks.…”

Objective stress values during radiation emergency medicine for future human resources: Findings from a survey of nurses

“…HRV refers to the variation in the RR interval of the electrocardiogram, which indicates the instantaneous heart rate, and is affected by the balance between the sympathetic and parasympathetic nervous systems. The low-frequency/highfrequency ratio (LF/HF) obtained from the analysis of the HRV frequency is used as a surrogate parameter for sympathetic overactivity and is associated with stress load [31][32][33]. There are several reports on the validity of HRV in assessing stress levels [34][35][36][37].…”