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TTEENTracking emotions, energy & neurostress

🧠 The science

Stress doesn't just feel bad.

As a teenager designing a device for burnout, I needed real evidence. Here is the research behind TEEN — the short version first.

The short version

Research links ongoing stress with changes in how you:

Think

Learn

Sleep

Focus

React

411

Students surveyed in the classroom study on demands and coping resources (167 boys, 244 girls).

50

Participants per group in the acute-stress experiment on mental effort.

11 wks

Length of the intervention in the probiotic-milk sleep and exam-stress trial.

Below is the full detail: six studies on how stress is defined, what causes it in teenagers, how researchers measure it, what differs between groups, and what reduces it.

Study 1

What is stress?

The American Psychological Association defines stress as a physiological or psychological response to internal or external stressors, which can disrupt a person's equilibrium and overall well-being. In the study published by Lazarus et al., stress is defined as any situation in which external and internal demands exceed the individual's ability to adapt and cope, disrupting mental, emotional and physical health.

Perceived stress — how the individual perceives and responds to reality and its challenges — is influenced by individual differences and environmental factors. Chronic stress and the inability to cope with it can lead to significant mental and physical health issues, including anxiety, depression, and sleep and eating disorders.

How is stress recognized?

  • Rapid heartbeat, sweating, dry mouth, shortness of breath
  • Headaches, dizziness, nausea, digestive issues
  • Sleep problems, pain, frequent illness, prolonged fatigue

Teenagers experience stress through homework and lessons, which negatively affects their self-rated health and sometimes their objective health status. Only one third of students who experience stress in school rate their health as excellent, and older students with heavier workloads report lower self-rated health.

Note: stress is not always negative. Moderate levels can be motivating and lead to personal growth — what matters is recognizing when stress stops helping.

Sources

Study 2

Stress in teenagers

Teen stressors

  • School obligations: lessons, homework, tests and high academic demands
  • Extracurricular activities
  • Social situations: conflicts with peers, family problems
  • Negative experiences at school
  • Life changes, such as moving home or changing schools

School load

School life becomes more stressful with age. Satisfaction with school, and the sense of support from teachers and peers, decreases as pressure from school duties increases. Students in STEM programs reported higher stress than those in other programs, and anxiety and depression can in turn decrease academic performance.

Sources

Study 3

How do researchers measure it?

Stress tests & questionnaires

Learning, memory and decision making are impaired by stress, and these cognitive functions can be assessed with stress tests and questionnaires.
  • Trier Social Stress Test (TSST), Kirschbaum 1993 — public speaking with mental arithmetic tasks
  • Demand Selection Task (DST) — participants choose between two options requiring different levels of mental effort
  • Need for Cognition Scale (NFC) — cognitive effort and motivation
  • SHAPS — apathy questionnaire
  • Perceived Stress Scale (PSS), Cohen 1994 — chronic stress over recent months

Method and findings

Fifty participants were randomly assigned to a stress or control group.
  • Acute stress increased participants' preference for less demanding behaviors, while performance remained unchanged
  • Most subjects preferred the low cognitive effort option, with higher incidence in subjects under stress
  • Skin conductance rose in the stress group — normal is 1–20 µS; theirs was 42 µS

Sources

Study 4

Stress by gender

Research questions

  • Is the level of demands, the level of coping resources, and the combination of the two associated with different measures of stress in students?
  • Are there any differences between girls and boys?

A classroom questionnaire was completed by 411 students (167 boys, 244 girls). A subsample of roughly 190 of them also took part in a cortisol study, giving saliva samples at four points in an ordinary school day: immediately on waking, 30 minutes post-awakening, 60 minutes post-awakening and 8:00 p.m., quantified with a competitive radioimmunoassay.

Findings

  • Girls had higher cortisol output than boys, which may partly reflect biological differences
  • Girls experienced higher levels of demands, with no gender difference in access to coping resources
  • Girls more often felt unable to live up to the expectations placed on them
  • Girls reported higher academic aspirations, and correspondingly more stress

Sources

Study 5

Differences observed between groups of adolescents

What the surveys report

  • Adolescent girls more often report health complaints such as headaches, sleep difficulties and low mood than boys of the same age
  • Reported loneliness rises sharply between ages 11 and 15 in both groups
  • Boys are less likely to seek help for mental health difficulties, which can delay support
  • Academic and social expectations differ by group and by school context, and both are associated with reported stress

These are averages across large samples. They describe patterns in populations, not predictions about any individual student.

Why it matters for this project

  • Identifying health difficulties in young people earlier improves outcomes
  • Stress affects school performance, so measuring it is useful to schools as well as students
  • Sleep difficulties, irritability and headaches are commonly associated with stress
  • Everyone benefits from tools to recognize and manage stress earlier in life

Related reading: sex differences in the association between cortisol concentrations and laboratory pain responses.

Sources

Study 6

How to reduce stress

Probiotic milk, sleep and exams

A 2017 study on probiotic milk showed it can decrease stress and increase deep sleep before exams.
  • 50 subjects per treatment group, repeated over two consecutive years and pooled
  • A 2-week pre-intervention period and an 11-week intervention period, with the national examination at the end of week 8
  • Subjects drank either 100 ml of LcS-fermented milk or placebo milk once a day
  • Sleep efficiency was determined by EEG measurement
Read the study

Findings

  • Ingesting the probiotic milk led to a decrease in stress and an increase in deep sleep
  • The LcS milk showed a significant positive effect on OSA scores, sleepiness factors and sleep length

Psychological well-being was assessed with the GHQ (Goldberg and Hillier, 1979), personality traits with the NEO-FFI (Costa and McCrae, 1989), anxiety with the STAI (Spielberger et al., 1970) and recent sleep quality with the PSQI.

Sources

Full reference list

Everything cited on this page, in one place.

  1. Study 1. Lazarus, R. S. & Folkman, S. (1984). Stress, Appraisal, and Coping. Springer.
  2. Study 1. American Psychological Association — Stress topic page.
  3. Study 2. Inchley, J. et al. (2020). Spotlight on adolescent health and well-being: HBSC 2017/2018 international report. WHO Europe.
  4. Study 2. Östberg, V. et al. (2018). School demands and coping resources — associations with multiple measures of stress in mid-adolescent girls and boys. IJERPH, 15(10), 2143.
  5. Study 3. Kirschbaum, C., Pirke, K.-M. & Hellhammer, D. H. (1993). The 'Trier Social Stress Test'. Neuropsychobiology, 28, 76–81.
  6. Study 3. Cohen, S., Kamarck, T. & Mermelstein, R. (1983). A global measure of perceived stress. J. Health Soc. Behav., 24(4), 385–396.
  7. Study 3. Bogdanov, M. et al. (2021). Acute psychosocial stress increases cognitive-effort avoidance. Psychological Science, 32(9), 1463–1475.
  8. Study 4. Östberg, V. et al. (2018). School demands and coping resources — associations with multiple measures of stress in mid-adolescent girls and boys. IJERPH, 15(10), 2143.
  9. Study 5. Inchley, J. et al. (2020). Spotlight on adolescent health and well-being: HBSC 2017/2018 international report. WHO Europe.
  10. Study 5. World Health Organization (2021). Adolescent mental health fact sheet.
  11. Study 6. Takada, M. et al. (2017). Beneficial effects of Lactobacillus casei strain Shirota on academic stress-induced sleep disturbance. Beneficial Microbes, 8(2), 153–162.

The measures used in this research

What each instrument actually measures, and who publishes it.

  • GHQ — General Health Questionnaire

    A short screening questionnaire on recent psychological distress: sleep, concentration, confidence and mood over the past few weeks.

    Published by GL Assessment (Goldberg & Hillier, 1979). Licensed material.

  • NEO-FFI — NEO Five-Factor Inventory

    A 60-item personality measure covering openness, conscientiousness, extraversion, agreeableness and neuroticism.

    Published by PAR (Costa & McCrae, 1989). Licensed material.

  • STAI — State-Trait Anxiety Inventory

    Separates anxiety felt right now (state) from anxiety a person tends to feel generally (trait).

    Published by Mind Garden (Spielberger et al., 1970). Requires a license to administer.

  • PSQI — Pittsburgh Sleep Quality Index

    Scores sleep quality over the past month: how long it takes to fall asleep, how long you sleep, and how rested you feel.

    Developed at the University of Pittsburgh (Buysse et al., 1989).

These are clinical instruments, meant to be given and interpreted by trained professionals, so TEEN does not host or link copies of them. If you want to know how you're doing, use the stress check here, and talk to a school counselor or doctor if something feels serious.

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