Caffeine, Energy and Your Nervous System
For many of us, coffee is part of the daily routine. The smell, the warmth, the ritual — and of course the boost that helps us get going in the morning or push through an afternoon slump. But beyond that familiar buzz, what is caffeine actually doing in the body, and why might someone choose to take a break from it?
This month at Your Body Works, we’re focusing on Feel Good February — making small, intentional choices that support how our body and nervous system function. As part of that, our front desk team (Caroline, Darcie and Nicky) have all decided to give up caffeine for the month, which felt like a great opportunity to revisit how caffeine affects the nervous system and explore some alternatives.
Why caffeine?
Caffeine is a stimulant that has a direct effect on the brain and central nervous system. It’s often used to increase alertness, improve focus, or combat fatigue — which is why it can feel so helpful when we’re tired, stressed, or stretched thin.
Caffeine works by blocking adenosine receptors in the brain. Adenosine is a neuromodulator that promotes relaxation and sleepiness, so when it’s blocked, we feel more awake and alert. Caffeine also increases dopamine, which contributes to that short-term “feel good” effect.
The catch? These effects are temporary. Once they wear off, many people experience a crash — fatigue, irritability, or difficulty concentrating — which often leads to reaching for another coffee.
Caffeine, cortisol and your Sympathetic Nervous System
If you’re always on the go, feel like you’re on the edge of burnout, and never quite feel rested, you may be spending a lot of time in fight or flight mode (also known as sympathetic nervous system dominance), with chronically elevated cortisol levels.
When the body is in this state, it’s common to constantly reach for coffee, tea, or even sugar to get that temporary burst of energy just to keep going. It’s not a lack of discipline — it’s the nervous system asking for support.
Caffeine can amplify this response. As a stimulant, it further activates the nervous system and can increase cortisol levels, especially when consumed frequently or first thing in the morning. Over time, this can contribute to that wired-but-tired feeling — alert, but not calm or restored.
If this resonates with you, keep an eye out later this month for a dedicated blog on getting out of fight and flight mode, where we’ll talk more about practical ways to support nervous system regulation in everyday life.
Other effects of caffeine in the body
Caffeine can affect more than just energy and alertness:
Increases stomach acid and may contribute to reflux or heartburn
Has a diuretic effect and can contribute to dehydration
Can temporarily increase heart rate and blood pressure
In high doses, may contribute to irregular heart rhythms
Can interfere with calcium and iron absorption
May exacerbate anxiety symptoms in some people
There are also benefits when consumed in low to moderate amounts, including reduced risk of some chronic diseases and improved exercise performance. As with most things, context and amount matter.
How much is too much?
Safe caffeine intake varies from person to person, but general guidelines suggest:
Up to 400mg per day for most adults
Less than 200mg per day during pregnancy or breastfeeding
A single espresso typically contains around 80–100mg of caffeine. For many people, 2–4 coffees per day may not cause noticeable issues — but for others, even small amounts can impact sleep, mood, or anxiety.
How long does caffeine last?
Caffeine peaks in the bloodstream within 30–60 minutes, but its effects last much longer. The half-life of caffeine in adults is around 5–6 hours, meaning that an 8am coffee can still be affecting your nervous system well into the afternoon.
During pregnancy, caffeine is metabolised much more slowly, and in babies and young children it can take days to clear completely.
When breastfeeding, caffeine passes into breast milk, and because babies process caffeine very slowly, it can accumulate in their system. This may contribute to unsettled behaviour, increased wakefulness, or difficulty sleeping — sometimes many hours or even days after consumption.
If you’re noticing a wired or unsettled baby, or frequent night waking that doesn’t seem to have a clear cause, it’s worth considering caffeine intake as one possible contributing factor.
Caffeine alternatives our team is loving
One of the biggest challenges with reducing caffeine isn’t just the energy hit — it’s missing the comfort and ritual of a warm drink.
Some alternatives our team has been enjoying this month include:
Chicory coffee substitute (Nicky) – rich and roasted, with a coffee-like flavour
Cacao – still comforting and familiar, with a different taste and naturally supportive compounds
Hojicha (Darcie) – a traditional Japanese roasted green tea that is naturally very low in caffeine and gentle on the nervous system
Rooibos - a caffeine-free black tea can also be used to make a caffeine-free chai latte
All of these still offer that pause-and-sip moment without stimulating the nervous system in the same way.
Supporting energy without relying on coffee
If coffee has become your main source of energy, it’s often a sign the body needs support elsewhere. Some ways to help energy levels naturally include:
Eating regular meals with adequate protein and healthy fats
Prioritising sleep (even small improvements help)
Getting outside and moving gently during the day
Supporting nervous system regulation through breath, movement, and care
Chiropractic adjustments can also play a role by reducing physical stress on the nervous system and helping the body move out of fight/flight and into a more balanced state. When the nervous system is supported, energy tends to feel more steady rather than spiky.
A note on withdrawal
If you do decide to cut back on caffeine, it’s normal to experience withdrawal symptoms such as headaches, fatigue, irritability, or difficulty concentrating. These symptoms are temporary and usually settle within a few days.
Final thoughts
This isn’t about giving up coffee forever. For many people, coffee can absolutely be part of a healthy lifestyle. The goal is awareness — understanding how caffeine affects your body and nervous system, and making choices that support how you want to feel.
As part of Feel Good February, our team is using this month as a reset and a chance to check in. You might like to ask yourself:
How much caffeine am I having?
How does it affect my energy, mood and sleep?
Am I using it to support myself — or to push through?
Everything in moderation — and always with context.