How the body responds to danger
When we feel stressed, the body releases hormones called cortisol and adrenaline. These prepare us for fight or flight: an automatic response to danger that gets us ready to confront a threat or escape from it.
This response is thought to have evolved hundreds of thousands of years ago, helping people react to life-threatening situations. It places the brain on high alert and increases the heart rate, preparing the muscles with the energy needed to take action.
Today, everyday stress is more likely to involve psychological pressures than being chased by predators. Challenges at work and difficulties in relationships can nevertheless activate the same response. The body prepares for action even when the situation is not a physical threat that we can fight or run away from.
The difficulty is that these pressures can arise frequently, sometimes every day. A little stress can be useful: it may motivate us to meet a deadline or help us stay alert for a task. But when stress leaves us feeling continually overwhelmed, long-term, or chronic, exposure can affect both physical and mental health.
Why stress triggers vary
There is no single explanation for what causes stress. Its triggers are personal and depend on our experiences throughout life. Although people may share some sources of pressure, the range of things that can feel stressful is extensive.
Something you find stressful may not trouble someone else, and that difference is entirely valid. People respond differently to particular situations. Being gentle with yourself matters; another person's reaction does not make your own feelings less real. There are ways to help prevent and tackle stress when it arises, rather than simply being hard on yourself for experiencing it.
The effects of prolonged stress
A short-lived stress response can sharpen awareness and help us cope in an emergency. Problems can develop when it is activated too often or continues for too long, with stress hormones being released repeatedly.
Possible physical effects include stomach and digestive problems such as diarrhoea, constipation and nausea. Chronic stress can also weaken the immune system, contributing to regular colds and infections. Exhaustion, sleeping problems and heart disease are other physical health problems associated with prolonged stress.