The Nervous System, Stress and Your Health: Why Your Body Might Be Asking You to Slow Down

For many people, when life feels overwhelming, the body responds too, digestion can change, appetite might increase or decrease, sleep can be disrupted, and everyday things can start to feel harder.

That's because stress doesn't just affect the mind. It affects your entire nervous system. Understanding how the nervous system works can help make sense of why stress can show up in so many ways throughout the body, and why this is a protective response, not a flaw.

So, what is the nervous system?

Your nervous system is your body's communication network. It constantly receives information from your environment and sends signals throughout your body to help keep you safe and functioning. One of its key jobs is sensing whether you're safe or under threat and responding accordingly.

The autonomic nervous system has two main branches:

• Sympathetic nervous system (often described as fight or flight)

• Parasympathetic nervous system (often described as rest, digest and recover)

Both are essential, and both are doing their job when they activate. Difficulties can arise when stress is constant and the nervous system has fewer chances to return to a state of rest, recover and digest, this reflects how protective the nervous system is trying to be, not a personal failing.

When your brain detects a threat, whether it's masking to navigate day to day life, a difficult conversation, work pressure, financial stress or ongoing life pressures, the sympathetic nervous system can become activated, triggering the release of stress hormones including adrenaline and cortisol.

The body may begin preparing for action by:

• Increasing heart rate and blood pressure

• Redirecting blood flow away from digestion

• Increasing alertness and focus

• Releasing stored energy

• Temporarily deprioritising functions like digestion and reproduction

This response can be incredibly helpful in the short term, and it's designed to protect us. Our nervous systems evolved to respond to danger like a threatening animal and today they often respond to modern-day stressors in similar ways.

Bodies are designed to move in and out of stress responses. When stress becomes chronic and ongoing, as is often the case in our modern day lives, your nervous system may have less opportunity to fully recover, which is where some people start to notice changes.

Chronic stress activation has been linked to experiences such as:

• Digestive changes including bloating, constipation, diarrhoea and reflux

• Changes in appetite and eating patterns

• Fatigue and low energy

• Difficulty sleeping

• Increased anxiety and irritability

• Reduced concentration and memory

• Elevated inflammation

• Increased risk of chronic disease over time

Research suggests that prolonged exposure to elevated stress hormones may contribute to cardiovascular disease, metabolic conditions, immune dysfunction and poorer mental health outcomes. It's worth remembering that these experiences look different for everyone, and they reflect the body trying to adapt and protect itself, they aren't a sign of weakness or something being "wrong" with you.

Let's talk about stress and digestion: the gut-brain connection

One of the first places many people notice stress is in their digestive system. The gut and brain are constantly communicating through what's known as the gut-brain axis.

When the nervous system senses danger, digestion is often deprioritised.

For some people, this can look like:

• Feeling full quickly

• Nausea

• Abdominal discomfort

• Changes in bowel habits

• Increased gut sensitivity

For some people, chronic stress may also influence food choices, cravings and eating behaviours. This is a gentle reminder: this is a biological response, not a lack of willpower.

Some people notice a reduced appetite and find themselves forgetting to eat. Others may find comfort in food as the body looks for quick sources of energy or relief. Many people notice their eating shifts when stress is high, sometimes eating less than usual, sometimes eating more. Both are common nervous system responses, not something to judge yourself for.

This is why people seek support from a Dietitian at Dietetics Done Differently, we work together to understand your context, both historical and current, we look at more than just what you are eating. Together we get curious and understand the why. Supporting you to understand the language of your nervous system and developing the skills to support your nervous system is often an important part of supporting you with your relationship with food and eating.

Ideas that may support nervous system regulation

Everyone's nervous system, history and circumstances are different, so not everything here will suit everyone, these are options to consider, not a checklist to follow perfectly:

• Eating regularly and consistently, in a way that feels manageable for you

• Prioritising rest and sleep where you're able to

• Gentle movement or physical activity that feels good in your body

• Spending time outdoors, if this is accessible and enjoyable for you

• Connecting with supportive people, in ways that feel safe for you

• Mindfulness or relaxation practices that suit your preferences

• Breathing exercises, if these feel comfortable, they aren't the right fit for everyone, and that's okay

• Taking micro breaks during busy periods, when possible

Understanding context and function are key aspects of learning how to support your body, mind and nervous system for long term wellbeing If you're noticing that stress is significantly affecting your eating, sleep or day-to-day functioning, we are here to help. There's no single "right" way to support a nervous system, and what works well for one person may not work for another.

If you’re interested in exploring how we can support you, book a free discovery call.

---

References:

1.     McEwen BS. Protective and damaging effects of stress mediators. New England Journal of Medicine. 1998;338(3):171-179.

2.     Chrousos GP. Stress and disorders of the stress system. Nature Reviews Endocrinology. 2009;5(7):374-381.

3.     Dhabhar FS. Effects of stress on immune function: the good, the bad, and the beautiful. Immunologic Research. 2014;58(2-3):193-210.

4.     Carabotti M, Scirocco A, Maselli MA, Severi C. The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems. Annals of Gastroenterology. 2015;28(2):203-209.

5.     Cryan JF, O'Riordan KJ, Cowan CSM, et al. The microbiota-gut-brain axis. Physiological Reviews. 2019;99(4):1877-2013.

6.     Schneiderman N, Ironson G, Siegel SD. Stress and health: psychological, behavioural and biological determinants. Annual Review of Clinical Psychology. 2005;1:607-628.

7.     World Health Organization. Mental health, stress and wellbeing. Geneva: WHO; 2024.

8.     American Psychological Association. Stress effects on the body. Washington, DC: APA; 2024.