## 2 Materials and Methods
### Data Collection  
A total of 34 subjects participated in 166 clinical experiments approved by the Institutional Review Boards (IRB) at the universities conducting the experiments. Table 2 shows a general overview of the participants' demographics.  
The experiments involve being in a sedentary state (SS) or performing two types of PA, either treadmill running (TR) or stationary bike (SB). Subjects perform PA under no psychological stressor non-stress (NS), or under the influence of stressors that induces APS, either mental stress (MS) or emotional anxiety stress (EAS). The APS inducement methods are standard reliable techniques that have been reported in the literature in previous studies [1; 19; 22; 23; 29; 30; 31; 32; 33].  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Device** & **Sensor** & **Frequency of Measurement** \\ \hline Empatica E4 & \multirow{2}{*}{Gyroscope} & Continuous triple axis acceleration within \(\pm\)2 g with \\ Wristband & & frequency of 32 Hz \\ \hline Empatica E4 & \multirow{2}{*}{PPG} & Continuous BVP signal with sampling rate of 64 Hz \\ Wristband & & \\ \hline Empatica E4 & \multirow{2}{*}{Infrared Thermopile} & Continuous ST with the sampling rate of 4 Hz \\ Wristband & & \\ \hline Empatica E4 & \multirow{2}{*}{Electrodermal Continuous GSR with the \(\;\  
The SS experiments are divided into three subcategories: NS events, EAS inducement, and MS inducement. In NS, subjects perform free living activities such as reading books, watching neutral videos or surfing the internet. In EAS inducement, subjects meet with their supervisors to report progress of their work, drive a car, and solve test problems in a specific time frame. In MS inducement, subjects solve mental or mathematics exam or IQ test, or puzzle games or perform the Stroop test. Similarly, APS inducement during PA (TR and SB experiments) are split into three subcategories. An NS experiment involves watching natural videos or listening to music. During EAS inducement sessions, subjects watch surgery videos or car crash videos, while in MS inducement experiments, they solve mental math problems. Figure 1 describes the data acquisition system for the data collection.  
The Cosmed K5 portable indirect calorimetry system is used to measure the EE (the ground truth). To ensure the PA is consistent across all experiments, the EE was compared across NS, EAS, and MS. In addition, the State-Trait Anxiety Inventory Trait STAI-T and the State-Trait Anxiety Inventory State STAI-S scores are calculated for each participant to assess the anxiety response [34; 35; 36]. Before and after each nonstress and emotional anxiety stress inducement experiment, the State-Trait Anxiety Inventory (STAI) self-reported questionnaire is collected. The STAI-T scale consists of 20 statements that ask people to describe how they generally feel. On a daily basis, it describes how one feels stressed, anxious, or uncomfortable. The STAI-S scale also consists of 20 statements, but the instructions require subjects to indicate how they feel at a particular moment in time. It is used to determine the actual levels of anxiety intensity induced by the stressful experiment. Table 3 lists the experiments conducted for data collection.  
Figure 1: A schematic representation of the data acquisition system for the data collection.