Facts for Kids

Stress is what happens inside your body and mind when something in the world asks a lot from you. When you feel threatened, worried, excited, or very busy, systems inside you react. One important system is the autonomic nervous system, and another is the HPA axis. These systems help the body send out chemicals such as adrenaline and cortisol to get you ready to act.

The sympathetic nervous system speeds things up for action, while the parasympathetic system helps you calm down again. Stress can change memory, how your body fights germs, and how your energy is used, so it matters both for short moments and for longer times. What makes your body notice something as stressful?

The part of your body that reacts without you thinking is the autonomic nervous system. Its two sides do very different jobs. The sympathetic nervous system tells your heart to beat faster, opens airways so you can breathe better, and signals glands to release hormones. The other side, the parasympathetic system, slows things down so you can rest and digest food.

The HPA axis is a chain of organs and hormones that includes signals from the brain to the adrenal glands. It helps release cortisol, a hormone that changes how the immune system and energy use work. A little short stress can boost some brain chemicals and help focus, but long-term stress can weaken the part of the brain used for planning, attention, and working memory, making thinking harder over time.

Chronic stress means feeling stressed for a long time. Over weeks or months this can make you feel sad, worried, or always on edge. Sometimes people feel unreal or very jumpy after a severe scary time. Long-term stress raises the chance of ongoing mood problems like anxiety or depression.

Chronic stress also affects the body. It can make colds more likely, slow healing, and make some illnesses worse. In children, stressful homes or hard times can slow growth. The earliest years—before birth and in childhood—are very sensitive, so stress then can have strong effects later. What do you notice in your body when you feel stressed for a long time?

Not all stress is bad. Some stress, called eustress, feels exciting or helpful — like training for a sport, learning something hard, or getting ready for a fun performance. Eustress can boost energy, make your heart stronger, and help your brain work better when it is the right amount.

Psychologist Richard Lazarus said stress starts when we make an appraisal: first we judge if something is a threat or a challenge (primary appraisal), then we decide if we have ways to handle it (secondary appraisal). People cope by fixing the problem or by calming their feelings. Different people and different ages handle the same stress in different ways, and sometimes people change their strategy if the first one does not work.

Stressors are things that push your body or mind out of balance. They can be loud noises, pain, poor food or air, fights with friends, big life changes, not enough sleep, or having to do a hard test. Some stressors start before birth, and these can change how the body learns to handle stress as you grow.

When a stressor appears, the body goes into an early stage called alarm. At first you may feel weak or low on energy. Then the body moves into a quick reaction called fight-or-flight. It releases adrenaline to make your heart beat faster and muscles ready. A body system called the HPA axis then makes cortisol, which helps keep you alert. These steps help for short problems, but they can be hard on you if they happen all the time.

How much stress affects you depends on the gap between the situation and what you think you can handle. You first appraise a situation—that means you judge if it is dangerous or just a challenge. Coping can try to change the problem (like planning or asking for help) or change your feelings (like calming breaths or talking to a friend). People often switch strategies if one does not work.

Some people bounce back better; that is called resilience. Differences in genes, past experiences, and habits help explain this. A kind of helpful stress, called eustress, comes from things like practice or fun challenges and can make you stronger. Learning new ways to cope and getting support lowers health risks, so what helps you feel stronger when things get tough?

Homeostasis is the way your body keeps things steady inside — like temperature, energy, and salt levels — so your cells work well. When something in the outside world pushes those levels too far, your body must act to bring things back. That push-and-pull is what we call stress: it shows your body is trying to restore balance.

Fixing the balance uses energy and resources, and sometimes the fixing itself can be tiring. The scientist Hans Selye described stress as the body's general response to demands. If the demands are bigger than what your body can handle, stress grows and may last longer.