There is something I come back to again and again in my work with clients, something that cuts across every health conversation I have regardless of age, background, or the specific symptoms that brought them to me in the first place, and that is this – it’s not possible to meaningfully address heart health without addressing the nervous system. The two are not separate systems that occasionally interact.
They are, in the most literal physiological sense, in constant conversation with each other, every minute of every day, responding to your thoughts, your breath, your relationships, your unprocessed grief, your afternoon deadlines, and the way you slept last night. Understanding this conversation — and learning how to participate in it rather than simply being subject to it — is, I believe, one of the most powerful steps you can repeatedly take for the long-term health of your heart.
And yet this is rarely the conversation that happens.
What happens far more often is that heart health gets reduced to cholesterol numbers and step counts, which of course do matter. However, they miss something essential about the upstream conditions that determine whether the heart is operating in a state of ease or chronic alarm. The nervous system is that upstream condition, and for most people living modern lives, it is spending a great deal more time in alarm than ease, whether or not they feel consciously stressed, and whether or not anything dramatic is happening in their outer world.
What we actually mean when we talk about the nervous system and the heart
The autonomic nervous system — the part of your nervous system that operates largely below the threshold of conscious awareness, so it’s ‘automatic’ — has two primary branches, and both of them have direct and measurable effects on cardiovascular function.
The sympathetic branch is the one most of us know of – it’s the fight-or-flight system, the one that floods the body with adrenaline and cortisol in response to a perceived threat, raises heart rate, increases blood pressure, shifts blood away from digestion and toward the large muscles, and prepares the body for rapid action. This system is brilliant, and in a genuine emergency, it is lifesaving. The problem arises when it is chronically activated by threats that never fully resolve — financial pressure, relational tension, a culture of busyness, a constant low-grade sense of not being safe or not being enough — because it keeps the cardiovascular system in a state of elevated arousal that, over months and years, becomes genuinely damaging.
The parasympathetic branch is the counterpart, often called the rest-and-digest (and heal) system, and it is governed in large part by the vagus nerve — a long, wandering nerve that connects the brainstem to virtually every major organ in the body, including the heart.
When the parasympathetic system is well-resourced and active, heart rate slows and becomes more variable in a healthy way, blood pressure drops, inflammation reduces, digestion improves, and the whole internal landscape of the body softens into something more like safety.
The goal of nervous system regulation, as I understand and practise it, is not to eliminate the sympathetic response — this would be dangerous and impossible — rather to build enough parasympathetic resilience that the body can move fluidly between activation and rest, rather than getting stuck in the alarm state like a car with the accelerator pressed all the way to the floor.
Heart rate variability – the window into your autonomic health
One of the most revealing measures of nervous system and cardiovascular health is heart rate variability, or HRV — a term that sounds technical although describes something beautifully simple. Your heart does not beat with perfect metronomic regularity; the intervals between beats vary slightly, and the amount of that variation is a direct reflection of how well your autonomic nervous system is functioning.
High HRV — meaning more variation between beats — indicates a nervous system that is flexible, responsive, and well-balanced between its sympathetic and parasympathetic branches.
Low HRV, by contrast, indicates a system that is rigid and dominated by sympathetic activation, and it has been consistently associated with increased risk of heart attack, stroke, cardiac arrhythmia, heart failure, and all-cause mortality.
The reason this matters so much in the context of stress is that chronic stress is one of the most reliable suppressors of HRV. Every time the stress response fires and fails to fully resolve — every time cortisol stays elevated, every time the body doesn’t get to complete the physiological arc of activation and recovery — HRV declines a little. Over time, across months and years of modern life without adequate recovery, that decline becomes significant and measurable, and its cardiovascular implications are profound.
The good news, and this is the part I invite you to sit with for a moment, is that HRV is not fixed. It responds to how you live, and there are specific, evidence-based practices that reliably improve it.
A 2024 systematic review and meta-analysis published in the journal Life, titled ‘The effect of stress-reducing interventions on heart rate variability in cardiovascular disease,’ found that stress-reducing interventions produced meaningful, beneficial effects on HRV parameters in people with cardiovascular disease — across short-term and 24-hour assessments. The interventions studied included practices like yoga, mindfulness, biofeedback, tai chi, and cognitive behavioural approaches. 1
The vagus nerve – your body’s built-in calm circuit
The vagus nerve deserves its own section, because understanding it changes the way you think about everything from your breathing to your posture to the sound of your own voice. It is the primary vehicle of parasympathetic regulation in the body, and its ‘tone’ — referring to how well it is functioning and how active it is — is one of the most important determinants of cardiovascular health that most people have never heard of.
High vagal tone is associated with lower resting heart rate, better blood pressure regulation, reduced inflammation, improved emotional resilience, and a measurably lower risk of cardiac events.
Low vagal tone is associated with the opposite of all of those things, and it is what happens when the nervous system has been living in sympathetic overdrive for too long without adequate counterbalance.
What’s remarkable about the vagus nerve is its accessibility. Unlike many aspects of physiology, vagal tone can be directly and deliberately influenced through practices that are entirely free, require no equipment, and can be woven into ordinary daily life without disrupting it.
The breath is perhaps the most powerful of these. Slow, diaphragmatic breathing — where the exhale is consciously longer than the inhale — directly stimulates the vagus nerve through a mechanism called respiratory sinus arrhythmia, and it produces immediate, measurable reductions in heart rate and blood pressure. Six breaths per minute, often described as the resonance frequency of the cardiovascular system, appears to be particularly effective, and even ten minutes a day practiced consistently over weeks begins to shift baseline vagal tone in a meaningful direction.
Humming, singing, and chanting also stimulate the vagus nerve through its branches in the throat and vocal cords, which is part of why communities with strong traditions of communal singing consistently show up in research on longevity and wellbeing.
Cold water on the face — particularly the forehead and around the eyes — activates the diving reflex, a rapid parasympathetic response that slows heart rate almost immediately.
Even the way you eat matters – slow, unhurried meals eaten in a state of relative calm activate the parasympathetic system through vagal pathways, while rushing through food in a state of stress keeps the body in sympathetic dominance and impairs both digestion and cardiovascular function.
These are not peripheral lifestyle details. They are direct inputs into the nervous system’s operating state.
Chronic stress and the cardiovascular system – what’s actually happening inside
I think it’s worth being quite specific about the physiological mechanisms here, because sometimes understanding what is actually happening in the body makes the motivation to change far more immediate and personal.
When the stress response activates, cortisol and adrenaline cause the heart to beat faster and more forcefully, blood vessels to constrict, blood pressure to rise, and inflammatory cytokines to increase. Blood becomes slightly more viscous and more prone to clotting — useful if you’ve been physically injured, deeply problematic if this is happening daily in response to a difficult email. Glucose floods into the bloodstream to fuel rapid muscle action. Arterial walls experience increased mechanical stress. All of these responses, repeated day after day over years, contribute to arterial stiffness, endothelial damage, plaque formation, hypertension, and elevated cardiac risk in ways that show up clearly in the research.
What makes this particularly insidious is that many people who are chronically stressed don’t feel dramatically stressed — they’ve adapted to a baseline of activation that feels normal although is anything but!
The body has recalibrated its sense of what calm feels like, and in doing so, it has lost access to the genuine parasympathetic rest that the cardiovascular system depends on for repair, recovery, and optimal function. Rebuilding that access is not a luxury or a self-care indulgence — it is a cardiovascular intervention as legitimate and as measurable as any other.
Sleep – the non-negotiable foundation of nervous system and heart health
No conversation about nervous system regulation and heart health is complete without a specific discussion of sleep, because sleep is the single most potent autonomic reset available to us, and its cardiovascular implications are stark. During deep, non-REM sleep, the body shifts into profound parasympathetic dominance — heart rate drops, blood pressure falls, cortisol declines, inflammatory markers reduce, and the cardiovascular system undergoes a kind of physiological restoration that simply isn’t able to happen any other way. Consistently getting fewer than six hours of sleep per night has been associated in large epidemiological studies with significantly elevated risk of hypertension, coronary heart disease, and stroke — risks that persist even after controlling for other lifestyle factors.
The sleep architecture matters, not just the duration. It’s the deep slow-wave sleep in the early part of the night and the REM sleep in the later cycles that carry the most cardiovascular benefit, which means that the quality of your sleep environment and the consistency of your sleep timing are as important as the hours.
A bedroom that is genuinely dark, cool, and quiet — with a consistent sleep and wake time even on weekends — creates the conditions for the kind of restorative sleep that actively supports the nervous system’s capacity to regulate and recover. Avoiding caffeine after noon, limiting alcohol, and creating a wind-down ritual that signals to the nervous system that the day is genuinely over are all practical steps that people consistently underestimate until they actually implement them.
Movement as nervous system medicine
Exercise is often discussed primarily in terms of its effects on the cardiovascular system — and those effects are real and significant — however what I want to focus on here is something slightly different – the specific role that physical movement plays in nervous system regulation, and why the type and timing of movement matters in this context.
Aerobic exercise, particularly at moderate intensity, is one of the most effective evidence-based tools for improving HRV, reducing baseline cortisol, and building parasympathetic resilience over time. A regular walking practice, cycling, swimming, dancing — any sustained rhythmic movement that raises the heart rate moderately and involves full breathing — progressively trains the autonomic nervous system toward greater flexibility and balance.
What is less well understood outside specialist circles is that certain forms of movement are particularly effective for nervous system regulation because of their specific qualities.
Yoga is an excellent example — the combination of intentional breathing, slow movement, body awareness, and deliberate rest activates the parasympathetic system through multiple pathways simultaneously, and the research on yoga’s effects on HRV, blood pressure, and inflammatory markers is now substantial and consistent.
Tai chi achieves something similar through its flowing, meditative qualities and its emphasis on breath coordination.
Even simple, slow stretching practiced with attention to the breath can shift the nervous system measurably toward parasympathetic tone.
The key in all of these is the quality of attention brought to movement — doing it consciously, with breath awareness, rather than powering through it in a distracted, goal-oriented way that keeps the sympathetic system engaged throughout.
The nourishment your nervous system is quietly asking for
Nutrition and nervous system regulation are connected in ways that most of us are never told, and the heart sits at the intersection of that connection.
Magnesium is perhaps the most important micronutrient in this context — it is required for the proper functioning of the parasympathetic nervous system, for healthy heart rhythm, for blood pressure regulation, and for the modulation of the stress response at a cellular level, and it is chronically low in a large proportion of people eating modern Western diets.
Dark leafy greens, pumpkin seeds, almonds, black beans, dark chocolate, and avocado are all excellent magnesium sources, and consistently incorporating them into daily eating genuinely shifts the nervous system’s baseline.
Omega-3 fatty acids — found in flaxseeds, chia seeds, oily fish and walnuts — have direct anti-inflammatory effects on the cardiovascular system and also appear to support autonomic nervous system function and HRV, with several studies showing higher omega-3 intake associated with improved vagal tone.
The gut-brain axis matters here too – the vagus nerve is a primary communication channel between the gut and the brain, and a healthy, diverse gut microbiome — supported by fermented foods, a wide variety of plant-based fibre, and minimal ultra-processed foods — appears to send more calming, regulating signals up through that pathway than a disrupted one does. This is a relatively new area of research, however the direction of evidence is consistent and compelling.
Reducing stimulants — particularly caffeine in excess and alcohol — deserves mention as one of the most direct dietary interventions for nervous system regulation. Caffeine extends the half-life of cortisol and suppresses adenosine, the compound that drives the feeling of tiredness and that plays a role in parasympathetic regulation during rest. Alcohol, despite its short-term sedative quality, consistently disrupts sleep architecture, suppresses HRV, and leaves the nervous system in a more dysregulated state the following day.
None of these are about rigidity or deprivation — it is about understanding the actual physiological effects and making choices from that knowledge rather than from habit.
Building a nervous system regulation practice that actually sticks
Let’s finish with something practical, because information without application stays in our head and never reaches our heart — in both senses of the phrase! A nervous system regulation practice doesn’t need to be elaborate, or expensive, or time-consuming. It needs to be consistent, embodied, and honest — meaning it has to actually shift your physiology, not just tick a box. The practices with the strongest evidence base for improving autonomic function and cardiovascular outcomes are slow, extended-exhale breathing done daily; regular moderate aerobic exercise; adequate, consistent, high-quality sleep; genuine social connection and laughter; time in nature; and whatever creative or contemplative practice reliably brings you into a state of absorption and ease, whether that’s gardening, playing music, cooking slowly, or sitting quietly with a view that moves you.
The thread running through all of these is that they require you to actually arrive — to be present in your body, breathing, feeling, allowing the nervous system to complete the cycle of activation and rest rather than staying perpetually in the planning, worrying, managing, and doing that constitutes so much of modern life.
Your heart is not asking for perfection.
It is asking for regularity — regular signals of safety, of rest, of care, of the simple biological fact that you are here, alive, and not under threat. Sending those signals, consistently, across the weeks and months and years, is the practice.
And it is, genuinely, one of the most profound things you can do for the health of your heart.
See you on this week’s #AlivewithFi 🙂
Fi Jamieson-Folland D.O., I.N.H.C., is The LifeStyle Aligner. She’s an experienced practitioner since 1992 in Europe, Asia and New Zealand as a qualified Osteopath, Integrative Nutrition Health Coach, speaker, educator, writer, certified raw vegan gluten-free chef, and Health Brand Ambassador.
Facebook Instagram LinkedIn Pinterest YouTube
1 El-Malahi O, Mohajeri D, Bäuerle A, Mincu R, Rothenaicher K, Ullrich G, Rammos C, Teufel M, Rassaf T, Lortz J. ‘The effect of stress-reducing interventions on heart rate variability in cardiovascular disease – A systematic review and meta-analysis.’ Life (Basel). 2024;14(6) -749. Available at –https -//pubmed.ncbi.nlm.nih.gov/38929732/