Reference
Health glossary
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Plain-language definitions of the words that come up in the lessons, each with an everyday example.
Active listening
Listening to understand rather than to reply: full attention, reflecting back what you heard, and asking open questions before sharing your view.
Example: Instead of jumping in with advice, you say “So the hardest part was feeling ignored?” and let your friend keep talking.
Affect labelling
Putting a feeling into words. Studies suggest naming an emotion precisely can reduce its intensity a little.
Example: Noticing “I’m not just upset, I feel embarrassed” and saying it to yourself.
Allostatic load
The wear and tear on the body that builds up when the stress response stays switched on for a long time.
Example: Months of money worries and poor sleep leave someone getting ill more often and feeling constantly on edge.
Anxiety
A feeling of worry, unease or fear, often about what might happen. Some anxiety is normal; when it is persistent, intense and hard to control, a professional can assess whether it is an anxiety condition.
Example: Feeling a knot in your stomach the night before an exam is ordinary anxiety.
Assertiveness
Saying what you think, feel or need clearly and respectfully — between going quiet and going on the attack.
Example: “I can’t cover this shift, but I could swap with you next week.”
Attention
The mind’s spotlight: the limited capacity to focus on some things while filtering out others.
Example: You can follow a conversation or read a hard paragraph, but trying to do both at once, one of them suffers.
Attention restoration
The idea that tired, focused attention recovers with the right kind of break — especially time in nature or quiet, undemanding surroundings.
Example: A ten-minute walk in a park leaves you better able to focus than ten minutes of scrolling.
Avoidance
Staying away from something because of the uncomfortable feeling it brings. It gives short-term relief but tends to keep the fear or dread going.
Example: Leaving a difficult email unopened for weeks, which makes it feel even harder to open.
Behavioural activation
A well-supported approach for low mood: planning small, meaningful or enjoyable activities and doing them, rather than waiting to feel better first.
Example: Scheduling a 15-minute walk and a call with a friend on a week when you feel flat.
Behavioural experiment
Testing a fearful prediction with a small, safe real-life test, then comparing what happened with what you expected.
Example: Predicting “everyone will think I’m stupid if I ask a question”, then asking one and watching what actually happens.
Boundaries
Decisions about what you will and won’t do or accept, communicated kindly and clearly.
Example: “I don’t answer work messages after 8pm.”
Burnout
Exhaustion from long-term, unmanaged stress, usually at work: feeling drained, distant or cynical, and less effective. WHO describes it as an occupational phenomenon, not a medical condition.
Example: A nurse after months of double shifts who feels numb and no longer cares about work she used to love.
Caffeine half-life
The time it takes for half the caffeine you consumed to leave your body — around five hours on average, and longer for some people.
Example: A coffee at 4pm can still leave a meaningful amount of caffeine in your body at bedtime.
Catastrophising
A thinking pattern that jumps to the worst possible outcome and treats it as likely.
Example: Thinking “this mistake will get me fired and I’ll never work again” after a small error.
CBT for insomnia (CBT-I)
A structured programme for long-term sleep problems, recommended by major guidelines as the first treatment for chronic insomnia.
Example: Learning to get up when you can’t sleep and keeping a fixed wake time, with a trained professional’s guidance.
Chronic stress
Stress that lasts for a long time — weeks, months or years — without the body getting a chance to recover.
Example: Caring for a sick parent alongside a full-time job for a year.
Circadian rhythm
Your body’s internal clock, running roughly every 24 hours, which controls sleepiness, alertness, hormones and more. Light is its main setting signal.
Example: Feeling sleepy at about the same time each night, and groggy after flying across time zones.
Cognitive behavioural therapy (CBT)
A well-researched talking therapy that works on the links between thoughts, feelings, body and behaviour, using practical skills.
Example: Using a thought record to test the thought “I always fail” against the evidence.
Cognitive restructuring
Examining a painful thought against the evidence and finding a more balanced, accurate way to see the situation. A core CBT skill.
Example: Replacing “she thinks I’m useless” with “she was busy; I have no evidence she’s unhappy with me”.
Commitment device
An arrangement made in a calm moment that makes it harder for your future self to break a promise.
Example: Paying for a class in advance, or arranging to meet a friend for a run so you can’t easily skip it.
Confirmation bias
The tendency to notice and remember evidence that fits what you already believe, and to miss evidence that doesn’t.
Example: Believing “nobody likes me” and remembering the one unanswered message while forgetting the friendly ones.
Context switching
Moving attention from one task to another. Each switch costs time and focus, even when it feels instant.
Example: Answering messages in the middle of writing a report, and taking longer to get back into the report each time.
Correlation vs causation
Two things happening together (correlation) doesn’t prove one causes the other (causation). A third factor, or reverse direction, may explain the link.
Example: People who use social media heavily may feel worse — but feeling worse might also lead people to use it more.
Cortisol
A hormone released as part of the body’s stress response. It helps you respond to demands but can cause problems if it stays high for long periods.
Example: Cortisol levels rise before a stressful exam and usually settle afterwards.
Cue
A trigger that prompts a habit — a time, place, feeling, person or preceding action.
Example: Putting on the kettle is the cue for taking out your notebook to plan the day.
Deep work
A term for sustained, distraction-free focus on a demanding task — writing, studying, solving a hard problem.
Example: Blocking 8–9am with your phone in another room to write the hardest part of an essay.
Delayed gratification
Choosing a later, bigger reward over a smaller, immediate one.
Example: Saving money each month for a course rather than spending it on small treats.
Depression
A common, treatable health condition in which low mood or loss of interest lasts most of the day, most days, for two weeks or more, often with changes in sleep, energy and concentration. Only a professional can assess it.
Example: Unlike a sad week after bad news, depression lingers and affects every part of daily life.
Doomscrolling
Scrolling through bad news or distressing content for long periods, even when it makes you feel worse.
Example: Reading crisis updates in bed for an hour and then lying awake anxious.
Dopamine
A brain chemical involved in motivation and in wanting or anticipating rewards — more about the pull toward something than about pleasure itself.
Example: The urge to check your phone in case something new has arrived, even when you rarely find anything satisfying.
Emotion
A response to something that matters to you, involving feelings, body changes and urges to act — such as fear, anger, sadness, joy or envy.
Example: Anger rising when someone treats you unfairly, with a hot face and an urge to speak up.
Emotional regulation
The ways people influence which emotions they have, when, and how they experience and express them.
Example: Taking three slow breaths and reframing a comment before responding to it.
Empathy
Noticing and understanding what another person is feeling, and checking rather than assuming.
Example: “You seem quiet today — is everything all right?”
Evidence level
A label describing how much research supports an idea — here: strong, moderate, emerging, practical technique, or unclear. It describes the research, never you.
Example: Behavioural activation is labelled “strong” because many trials support it; grounding is “practical” because it is simple and safe but little-studied alone.
Exposure
Facing feared situations gradually and safely, so the fear can rise and settle. One of the best-supported approaches for anxiety, usually guided by a professional for phobias, panic or OCD.
Example: Making a short phone call to a shop, then a longer one, as steps toward calls that feel frightening.
Fight or flight
The body’s fast stress response: heart rate, breathing and muscle tension rise to prepare you to act against a threat.
Example: Your heart pounding and hands shaking just before you speak in front of a crowd.
Flow
A state of deep absorption in a challenging activity, where time seems to pass quickly and distractions fade.
Example: Losing track of an hour while painting, coding or playing music.
Grounding
Bringing attention back to the present moment through your senses when your mind has run off into worry or panic.
Example: Naming five things you can see and four things you can feel when you feel overwhelmed.
Growth mindset
The belief that abilities can be developed with effort, good strategies and help. The idea is sound; claims about quick mindset lessons are debated.
Example: Thinking “I’m not good at maths yet” and trying a new study method, rather than “I’m just bad at maths”.
Habit
A behaviour that has become automatic through repetition in a stable context, so a cue triggers it with little thought.
Example: Brushing your teeth before bed without having to decide to.
Habit loop
The cycle that keeps a habit going: a cue, a behaviour, and a reward.
Example: Boredom (cue) leads to checking your phone (behaviour), which brings a moment of novelty (reward).
Habit stacking
Attaching a new habit to one you already do every day, so the old habit becomes the reminder.
Example: “After I pour my morning coffee, I write down my three priorities.”
Hydration
Having enough fluid in your body. Needs vary with body size, activity and climate; thirst and pale urine are reasonable guides for most healthy people.
Example: Drinking more on a hot day or after exercise, and noticing fewer afternoon headaches.
Implementation intention
An if–then plan that links a specific situation to a specific action, decided in advance.
Example: “If it is 7am on a weekday, then I put on my running shoes.”
Intolerance of uncertainty
Finding it very hard to live with not knowing what will happen. It is linked with worrying more.
Example: Needing to research every option for hours before making a small decision, to feel sure.
Loneliness
The painful feeling of a gap between the connection you have and the connection you want. Different from being alone.
Example: Feeling lonely at a busy party where nobody seems to really know you.
Melatonin
A hormone your body releases in the evening as darkness falls, signalling that it is night-time. Bright light in the evening can delay it.
Example: Dimming the lights an hour before bed helps your body’s natural evening signal.
Meta-analysis
A study that combines the results of many studies on the same question to get a more reliable overall answer.
Example: Pooling dozens of trials of exercise for low mood to estimate how much it helps on average.
Metacognition
Thinking about your own thinking — noticing how you are thinking, and changing approach when it isn’t working.
Example: Realising you have reread your notes three times without remembering them, and switching to testing yourself.
Mindfulness
Paying attention to the present moment — breath, body, sounds, thoughts — with openness rather than judgement.
Example: Noticing your mind has wandered to tomorrow’s meeting and gently bringing it back to your breath.
Mobility
How freely your joints move through their full range. It supports everyday comfort and tends to decline if unused.
Example: Being able to turn your head fully to check behind you, or get up from the floor easily.
Moderate-intensity activity
Movement that raises your heart rate and breathing so you can talk but not sing — such as brisk walking.
Example: A brisk walk to the shops where chatting is fine but singing would be hard.
Mood
A general emotional state that lasts longer than a passing feeling — like feeling low, calm or irritable for a day.
Example: Waking up flat after a bad night and feeling that way through the morning.
Motivation
The drive to act. It rises and falls with sleep, stress, meaning and whether a task feels chosen, possible and shared.
Example: Feeling keen to practise guitar once you are playing with a friend again.
Negativity bias
The tendency for negative experiences to stand out and weigh more than positive ones.
Example: Remembering one critical comment from a meeting and forgetting three compliments.
Nervous system
The body’s communication network. One branch prepares you for action (fight or flight); another helps you rest and recover.
Example: Slow breathing with a long out-breath engages the branch that helps the body settle.
Notification
An alert from an app or device designed to pull your attention back to it.
Example: A buzz telling you someone liked your post, arriving in the middle of your work.
Perfectionism
Holding extremely high standards combined with harsh self-criticism and fear of mistakes. It is often linked with procrastination.
Example: Not starting a project because it has to be perfect, and rewriting the first line again and again.
Placebo
A treatment with no active ingredient. Comparing a real treatment with a placebo shows how much of an effect comes from the treatment itself.
Example: A trial gives some people a new remedy and others an identical-looking dummy, without anyone knowing which they got.
Present bias
Valuing rewards now much more than rewards later, even when the later reward is bigger.
Example: Choosing another episode tonight over a well-rested tomorrow.
Problem solving (structured)
Working through a problem in steps: define it, list options, weigh them, choose one, plan, then review.
Example: Turning “I have too much coursework” into a plan to ask for an extension and swap a work shift.
Procrastination
Putting off something you intend to do even though you expect to be worse off for it — usually to avoid an uncomfortable feeling.
Example: Cleaning your whole room instead of starting a dreaded application.
Progressive muscle relaxation
Tensing and then releasing muscle groups one at a time, to notice and let go of physical tension.
Example: Squeezing your shoulders up for five seconds, then dropping them and feeling the difference.
Psychological flexibility
Making room for difficult thoughts and feelings while still acting on what matters to you.
Example: Feeling nervous about joining a club, and going anyway because it matters to you.
Randomised controlled trial
A study where people are randomly assigned to receive a treatment or a comparison, so differences in results can be credited to the treatment.
Example: Randomly giving half a group a sleep programme and half the usual advice, then comparing their sleep.
Reappraisal
Changing how you interpret a situation so it affects you differently — a well-studied way of managing emotions.
Example: Seeing a tough interview as practice that taught you what they ask, rather than only as a failure.
Reframing
Looking at the same facts from a different, more complete angle — not pretending, but seeing more of what is there.
Example: “This delay is frustrating, and it also gives me time to prepare properly.”
Resilience
The ordinary ability to adapt and recover in the face of difficulty, built from relationships, skills and circumstances. It includes struggling, not avoiding it.
Example: Grieving a lost job, leaning on family, and slowly rebuilding a routine and confidence.
Rumination
Going over and over something that has happened — especially how bad you feel — without reaching anything new.
Example: Replaying a friend’s cancelled plans all weekend, asking what you did wrong.
Sedentary behaviour
Time spent sitting or lying down while awake, using little energy — such as desk work, driving or watching TV.
Example: Nine hours at a desk plus two hours on the sofa in the evening.
Self-compassion
Treating yourself with the kindness you would offer a friend when things go wrong, remembering that struggle is human, and noticing pain without drowning in it.
Example: “This is hard. Everyone slips sometimes. What would help me right now?”
Self-efficacy
Your belief that you can do something. It grows most from actually doing it.
Example: After asking one question in each meeting for three weeks, speaking up starts to feel normal.
Self-talk
The running commentary in your head about yourself and what is happening.
Example: “Come on, you’ve got this” — or “you idiot” — after a mistake.
Sleep debt
The shortfall that builds up when you regularly sleep less than you need.
Example: Sleeping six hours on weeknights and ten at weekends, and still feeling tired on Monday.
Sleep hygiene
Everyday habits and surroundings that support good sleep — a regular schedule, a dark and quiet room, a wind-down, less late caffeine.
Example: Charging your phone outside the bedroom and keeping the same wake time every day.
Sleep inertia
The groggy feeling after waking, especially from a long nap or deep sleep.
Example: Feeling foggy and slow for half an hour after a two-hour afternoon nap.
Social comparison
Judging yourself by comparing yourself with others. Online, it often means comparing your ordinary life with others’ highlights.
Example: Feeling behind after scrolling past classmates’ job announcements and holidays.
Social support
Help and care from other people — listening, practical help, advice or company.
Example: A sister who calls every Sunday and helps you think through a hard week.
Stimulus control
A sleep technique: if you can’t sleep, get up and do something calm until sleepy, so your bed becomes linked with sleep rather than being awake.
Example: Reading on the sofa for a while after 20 minutes awake, then returning to bed when drowsy.
Strength training
Activity that makes muscles work against resistance — body weight, weights, bands or heavy everyday tasks.
Example: Chair sit-to-stands and wall push-ups twice a week.
Stress
The body and mind’s response to a demand. Useful in short bursts; harmful when it goes on for a long time without recovery.
Example: A racing heart and sharp focus before a deadline, easing once it has passed.
Stressor
Anything that places a demand on you and triggers the stress response.
Example: A deadline, an argument, money worries or caring for someone who is ill.
Systematic review
A careful summary of all the good-quality research on a question, often including a meta-analysis.
Example: Reviewing every trial of mindfulness for stress to see what the evidence shows overall.
Task switching
Shifting between different tasks. Research shows each switch has a cost in time and accuracy.
Example: Jumping between an essay and messages, and making more mistakes in both.
Temptation bundling
Pairing something you should do with something you enjoy, so the treat pulls you toward the task.
Example: Only listening to your favourite podcast while walking.
Thinking trap
A common pattern a stressed mind falls into, such as all-or-nothing thinking, mind-reading or fortune-telling. Useful to notice in your own thinking — never a label for someone else.
Example: Noticing “I’m fortune-telling again” when you are sure a presentation will go badly.
Thought record
A structured worksheet for testing a painful thought: the situation, feelings, the thought, evidence for and against, and a balanced alternative.
Example: Writing down “my manager is unhappy with me”, listing the evidence, and finding it doesn’t hold up.
Timeboxing
Giving a task a fixed slot of time and working on it until the time is up, rather than until it is finished.
Example: Working on a CV from 10:00 to 10:30, then sending the draft for feedback.
Trigger
Something that reliably sets off a reaction — such as stress, a craving or a habit.
Example: Checking work email on Sunday evening triggers a wave of dread about the week.
Ultra-processed food
Foods made mostly from ingredients extracted from foods or made in factories, such as many packaged snacks and soft drinks. How much processing itself harms health is still debated.
Example: Instant noodles and fizzy drinks are ultra-processed; frozen vegetables and tinned beans are processed but much less so.
Urge surfing
Noticing an urge — to check your phone, snack or smoke — and riding it like a wave as it rises, peaks and falls, without acting on it.
Example: Feeling the pull to open an app, breathing through it for a minute, and noticing it fade.
Vagus nerve
A major nerve linking the brain with the heart, lungs and gut. It plays a part in the body’s “rest and digest” response.
Example: Slow breathing with a long out-breath is thought to calm the heart partly through the vagus nerve.
Values
What you want your life to stand for — directions you can keep moving in, like kindness, honesty or learning, rather than goals you finish.
Example: Valuing family, and protecting one dinner a week together.
Variable reward
A reward that comes unpredictably. Unpredictable rewards keep behaviour going more strongly than predictable ones.
Example: Refreshing a feed because sometimes there is something exciting — and often there isn’t.
Wind-down
A short, repeated evening routine that helps your body and mind shift toward sleep.
Example: Dim lights, a shower, writing tomorrow’s list and reading before bed.
Worry
Repetitive thinking about possible future problems. Unlike problem solving, it tends to go round in circles without reaching a next step.
Example: Lying awake thinking “what if I fail?” again and again.
Worry time
A set daily slot for dealing with worries, so that at other times they can be noted and postponed.
Example: Jotting a worry down at lunch and coming back to it at 5:30pm.