Life Science Hardware and Software

Stress has negative effects on the health of the body and the health of economies. When a person is feeling stress, the body releases certain chemicals that lower the immune system, increasing the likelihood that illnesses will form in the body. Stress can also cause negative effects in the workplace, as when workers take time off and seek treatment, the companies they work for lose money as well. The Mental Health Foundation estimates that around 12 million adults living in the United Kingdom visit their General Practitioner every year with concerns of their mental health that have been brought on by stress. Due to these illnesses, an estimated 13.3 million work days are lost every year. The World Health Organization estimates that around 8.4 million GBP (10.5 million USD) are lost by UK businesses due to these health concerns. Moreover, the average wait time to get treatment is 3-6 months. Because of these factors, over the last decade studies performed on stress and mental health have increased in popularity. Researchers, Mozos, Oscar Martinez, et al. aimed to detect stressful behaviors by having their participants wear noninvasive physiological monitoring systems to find what activities elicited stress. These experiments were performed in a laboratory setting, using the TSST (Tier Social Stress Test) to manage levels of anxiety in each participant in a controlled situation; this popular method was used in over 4,000 settings over the last decade. The total sample size the researchers used was 18, male and female volunteers from the School of Psychology at the University of Lincoln in the UK. The social task presented was for the subject to prepare a presentation for a mock job interview, and tasked to speak continuously for five minutes. When subjects paused the first time, the experimenter would tell them their remaining time and ask them to continue. The second time the participant paused they would be asked a set of predefined interview questions. For the cognition task, the experimenter asked the participant to count down from 1022 in sets of 13, for five minutes. If the participant made a mistake, they were asked to start from 1022 again. Using the wearable, dual-signal BioNomadix, researchers wirelessly recorded electrodermal activity (EDA) and pulse plethysmograms (PPG), then analyzed the data to gather the Heart Rate Variability (HRV) between different tasks the subjects were doing, and extrapolate the stress the subjects were feeling in those conditions. The goal of the researchers was to show that using wearable monitoring systems can help detect stress, and with variations, can be applied outside of the lab, and into everyday interactions to get a firmer grip on what is causing anxiety and stress in millions of people.

I think I’ll go to the gym…

Scientists have long used the power of physiological signals to make inferences about cognitive processes. To bridge the gap between physiology and psychology, exercise scientists often find it interesting to look at a person’s encephalographic brain frequencies (EEG) during settings of physical stress, or namely, exercise. Several studies in the past have aimed to evaluate how the mind operates during strenuous training, but what happens when someone just thinks about exercising?

Researchers Berk et al. have recently performed a study in which various athletes were asked to simply sit, close their eyes, and visualize themselves in a state of rest while their brains were monitored for EEG activity. Participants then were asked to visualize themselves in a state of heavy exercise or physical training. The researchers monitored the athletes’ brain EEG signals using a B-Alert X10 Telemetry system. What they found was a significant difference in brain state, primarily shown by the disparity in gamma wave frequency between visualizations of exercise and rest settings. These results suggest that mental visualization of complex physical tasks may support the construction of functional neural networks in the brain necessary for performing them. This study opens the door to subsequent research in order to understand more about the psychology of physical activity. BIOPAC Systems offers the wireless B-Alert X10 EEG system as well as other wearable and wireless solutions for psychophysiological and exercise research. These options include Mobita 32 channel wearable EEG and biopotential systems and the BioNomadix line of wireless biopotential and transducer amplifiers. These products have been consistently proven to provide accurate, reliable data whether the person wearing them is on the field training, or sitting at home just thinking about it.

The negative effects of stress on the body have been widely studied. Stress can be defined as a situation that is causing the current state, or homeostasis, under pressure to change. The human body’s nervous system reacts to stress by changing the amount produced of certain biomarkers. For example, when heart rate elevates, blood pressure rises and the human body reacts and secretes hormones (epinephrine, cortisol, etc.). Experimenters tested the change in the production of specific biomarkers of people with different training backgrounds to understand how acute psychological stress affects their physiological responses. The three group classifications were sedentary subjects, endurance athletes, and strength athletes.
 
EDA (skin conductance), ECG (EKG), and breathing frequency were measured continuously; BP and cortisol were measured after each experiment segment. EDA, ECG, and breathing frequency were measured during the acute psychological stress test using the BIOPAC MP150 data acquisition unit connected to wireless biopotential amplifiers and recorded on BIOPAC’s AcqKnowledge software.

Psychological stress was induced in participants using a Stroop color-word test and math problems. These problems were presented in a slide show where the subjects had a limited amount of time to solve for the correct answers. The researchers found numerous differences in changes in the biomarkers measured in response to the acute psychological stress activities between the three groups. On average, athletes’ cortisol levels changed differently when compared to the sedentary group. Also, skin conductance was shown to have higher levels in the sedentary group than in the athletes. The athletes also had a higher recovery level for systolic blood pressure, which was observed to decrease over the test for the sedentary group.
 
The participants reported to have experienced psychological stress over the course of the activities and this was reinforced by the change in values of the biomarkers measured. This experiment showed that people with different training backgrounds had different responses to psychological stress for related biomarkers. The experimenters concluded that people with different training backgrounds react differently in their changes of certain biomarkers to psychological stress.