How to Increase HRV: A Science-Based Guide to Supporting Autonomic Balance

Heart rate variability (HRV) has become an increasingly discussed marker of physiological resilience, recovery capacity, and autonomic nervous system balance^1,2. Many people searching for how to increase HRV are not looking for performance hacks alone, but for ways to support recovery, resilience, and physiological flexibility in daily life^2,3.

HRV reflects how effectively the body adapts to internal and external demands^1,2. Rather than focusing on heart rate itself, HRV captures the subtle variation between successive heartbeats - a signal influenced by sleep, stress load, physical activity, and parasympathetic signalling^1,3. Understanding how to increase HRV levels therefore requires looking beyond a single intervention and toward the systems that regulate autonomic balance over time^1,2.

This article explains how to increase HRV using evidence-informed lifestyle strategies, and explores how non-invasive vagus nerve stimulation approaches, including tools like Nurosym, may support autonomic regulation as part of a broader routine^12,13,14.

What HRV Represents in the Body

Before exploring how to increase your HRV, it is important to clarify what HRV does and does not represent. HRV is not a measure of “cardiovascular fitness” in isolation, nor is it a direct indicator of emotional state or overall health. Instead, HRV reflects the flexibility of autonomic control, capturing how effectively the nervous system adapts to internal and external demands^1,2.

HRV as a Window Into Autonomic Regulation

This autonomic control is governed by two complementary branches of the nervous system. The sympathetic branch supports mobilisation, alertness, and action, preparing the body to respond to physical or psychological demands^1,3. In contrast, the parasympathetic branch supports restoration and recovery, slowing the heart rate, facilitating digestion, and enabling physiological repair. HRV reflects the dynamic interplay between these two systems. When parasympathetic influence is flexible and responsive, heartbeats naturally vary more from moment to moment, resulting in higher HRV^1,2. When sympathetic activity remains dominant for prolonged periods, this variability is often reduced³.

Higher HRV values are generally associated with stronger parasympathetic modulation and more adaptive stress responses, while lower HRV may reflect sustained sympathetic dominance or reduced vagal tone^1,3. However, absolute HRV values vary widely between individuals due to age, genetics, biological sex, medication use, and baseline autonomic patterns^1,5. As a result, discussions around how to increase your HRV score are most meaningful when focused on individual trends over time rather than comparison to population norms^1,5.

Why HRV Is Sensitive to Daily and Cumulative Stress

HRV is highly responsive to cumulative physiological load. Factors such as poor sleep, prolonged cognitive stress, insufficient recovery, illness, or sustained emotional strain can all influence autonomic balance and reduce HRV^3,4. Importantly, these influences are often subtle and additive rather than acute³.

This explains why attempts to improve HRV through short-term tactics may yield inconsistent results. Sustainable improvements in HRV typically reflect changes in how the nervous system is supported across days and weeks, not hours^1,3. For those individuals exploring how to increase HRV, this reinforces the importance of consistency rather than intensity^2,3.

How to Increase HRV Through Behavioural Regulation

Behavioural strategies that support parasympathetic activity remain foundational when considering how to increase your HRV. Breathing patterns, physical movement, and recovery behaviours all influence vagal signalling through well-described physiological pathways^1,6.

Slow, controlled breathing has been consistently shown to enhance parasympathetic modulation and HRV by strengthening respiratory-linked heart rate variability and baroreflex engagement1,6. This effect is most pronounced when breathing is paced and unforced, rather than effortful or prolonged⁶.

Slow, controlled breathing has been consistently shown to enhance parasympathetic modulation and HRV by strengthening respiratory-linked heart rate variability and baroreflex engagement1,6. This effect is most pronounced when breathing is paced and unforced, rather than effortful or prolonged⁶.

Physical activity also plays a role, but with important nuance. Moderate, regular movement is associated with higher resting HRV, whereas excessive training load without adequate recovery may suppress HRV over time. From an autonomic perspective, recovery capacity matters as much as exertion itself^7,8.

Thermal and sensory inputs, such as brief cold exposure or gentle tactile stimulation, may also influence vagal reflexes, although responses vary depending on baseline autonomic state, stress load, and individual sensitivity^9,10. These strategies are best understood as supportive inputs rather than primary drivers of long-term HRV adaptation^1,2,3. 

How to Increase HRV During Sleep

Sleep is one of the strongest regulators of overnight HRV and overall autonomic recovery^1,11. Many people searching how to increase HRV during sleep underestimate how strongly sleep timing, consistency, and pre-sleep nervous system state influence nocturnal parasympathetic activity¹¹.

During non-REM sleep, parasympathetic dominance increases and HRV typically rises as metabolic and cognitive demands decrease. Disruptions to sleep architecture, circadian misalignment, or heightened pre-sleep arousal can blunt this response¹¹.

Supporting normal autonomic recovery during sleep therefore involves more than total sleep duration. Consistent bedtimes, reduced cognitive stimulation in the evening, and practices that facilitate parasympathetic down-regulation before sleep all help create conditions in which HRV can reflect effective overnight recovery¹¹.

Neuromodulation and HRV: Moving Beyond Indirect Approaches

In recent years, interest has expanded toward interventions that directly influence autonomic pathways involved in HRV regulation. Transcutaneous (through skin) auricular vagus nerve stimulation (taVNS) has emerged as a non-invasive method of modulating parasympathetic signalling through afferent fibres projecting to brainstem autonomic centres^12,13.

Unlike behavioural strategies that influence HRV indirectly, neuromodulation approaches target neural circuits involved in autonomic reflex control^12,13,14. This distinction has prompted increasing research into how such interventions may support autonomic balance when used alongside lifestyle foundations^13,14,15.

Nurosym by Parasym: Depth of Scientific Evidence, Not Marketing Claims

Parasym has contributed to one of the most extensive clinical research portfolios in the field of transcutaneous auricular vagus nerve stimulation (taVNS). Across more than 50 completed clinical studies, Parasym-developed stimulation protocols have been evaluated in healthy participants and in populations with autonomic and cardiovascular dysregulation.

61% Increase in Vagal Parasympathetic Activity (HF Power) vs Placebo

Clinical research has shown that auricular vagal neuromodulation using Parasym technology is associated with a 61% increase in vagal parasympathetic activity, measured using high-frequency (HF) power of heart rate variability, compared with placebo stimulation¹⁸.

HF power reflects vagally mediated parasympathetic input to the heart and is widely used in autonomic research as a marker of parasympathetic engagement. In this research, changes were observed following structured stimulation protocols and were consistent with a shift toward parasympathetic predominance rather than non-specific arousal or expectancy effects¹⁸.

18% Increase in HRV Following Nurosym Neuromodulation

In the same controlled study framework, Nurosym neuromodulation was associated with an 18% increase in overall heart rate variability (HRV) compared with placebo¹⁹.

HRV reflects the nervous system’s capacity to adapt dynamically to internal and external demands. Improvements in HRV are generally interpreted as enhanced autonomic flexibility and recovery capacity, particularly when driven by parasympathetic mechanisms rather than changes in heart rate alone.

Importantly, these HRV changes were not transient. Follow-up measurements indicated a carryover effect, with autonomic markers remaining elevated beyond the active stimulation phase, suggesting a neuromodulatory influence rather than a short-lived physiological fluctuation¹⁸.

Figure: RMSSD is a heart rate variability (HRV) measure sensitive to parasympathetic (vagal) activity, with higher values indicating greater autonomic flexibility. In a randomised, placebo-controlled study, Nurosym neuromodulation was associated with increased RMSSD compared with baseline and placebo, with effects persisting into the recovery phase, suggesting a carry-over effect.

 

Figure: Heart rate variability (HRV) responses following a one-hour session of auricular stimulation. HRV reflects autonomic nervous system regulation, including vagal-mediated parasympathetic activity. Compared with placebo, Nurosym was associated with significant changes in frequency-domain HRV measures after one hour, including a reduction in LF/HF ratio (*p = 0.002), consistent with modulation of autonomic balance.

34% Improvement On Cardio-Vagal Baroreflex Gain

Beyond HRV alone, in patients with chronic heart failure, Nurosym neuromodulation has been shown to be associated with a 34% improvement in cardio-vagal baroreflex gain compared with baseline. As baroreflex gain is a key marker of autonomic cardiovascular reflex function, this finding suggests enhanced parasympathetic engagement following auricular vagal neuromodulation.

In addition to cardiovascular and autonomic markers, Nurosym has been investigated across a range of symptom domains commonly associated with autonomic dysregulation. Clinical studies have examined its interaction with physiological markers and patient-reported measures in contexts characterised by anxious states, low mood, persistent fatigue, sleep disruption, cognitive strain, and stress-related symptoms^17,19.

Importantly, Parasym’s research programme has also placed strong emphasis on safety and tolerability. A pooled analysis across cardiovascular studies reported no device-related serious adverse events and only minor, transient sensations at the stimulation site, supporting suitability for repeated use¹⁷.

Figure: Cardio-vagal baroreflex gain (BRS), expressed as ms/mmHg, before and after Nurosym neuromodulation in patients with chronic heart failure. BRS reflects the sensitivity of autonomic reflex control of heart rate in response to blood pressure changes and is commonly impaired in heart failure. In this study, acute auricular vagal neuromodulation was associated with a significant increase in cardio-vagal baroreflex gain compared with baseline (p < 0.001), consistent with enhanced parasympathetic cardiovascular regulation¹⁶.

How Nurosym Fits Into an HRV-Supportive Routine

Nurosym is a non-invasive vagus nerve stimulator that delivers controlled electrical stimulation to the auricular branch of the vagus nerve. Nurosym is positioned to support parasympathetic signalling as part of a broader routine that includes sleep regulation, behavioural pacing, and recovery-focused practices, aligning with the current scientific understanding of HRV as a dynamic marker influenced by multiple interacting systems^1,5,13,14,15.

For individuals exploring how to increase HRV levels, neuromodulation may offer a way to reinforce parasympathetic engagement, particularly when behavioural strategies alone are insufficient or inconsistent.

Why HRV Changes Gradually Over Time

A common misconception around how to increase your HRV score is that meaningful change should occur rapidly. In practice, HRV reflects cumulative autonomic inputs over time, and sustained improvements tend to emerge gradually as overall physiological load decreases and recovery capacity improves. Sleep consistency, stress exposure, physical activity, and parasympathetic engagement all contribute incrementally, rather than producing immediate shifts^1,2,3.

Short-term fluctuations in HRV are therefore normal and should not be overinterpreted. Day-to-day variation may reflect transient stressors, poor sleep, or changes in routine, while longer-term trends offer more meaningful insight into how the nervous system is adapting over weeks rather than hours^1,5.

Within this context, Nurosym is designed to support consistency rather than immediacy. Developed by Parasym, Nurosym offers a compact, wellness-focused wearable system intended for regular use as part of everyday routines. Its lightweight design, adjustable intensity settings, and ergonomic ear interface are engineered to integrate comfortably into daily life at home, whether during focused work, post-exercise recovery, or evening wind-down.

Supported by real-world use across more than four million completed sessions, Nurosym provides a science-aligned way to explore auricular vagus stimulation device as a supportive input to autonomic regulation. Rather than aiming to override natural nervous system rhythms, its role is to complement behavioural foundations and encourage parasympathetic engagement over time, aligning with the gradual nature of HRV adaptation^13,14,15.

How to Increase HRV: Key Takeaways for Autonomic Regulation

Rather than viewing HRV as a performance metric to optimise, it may be more useful to frame HRV as a reflection of nervous system adaptability^1,2. Supporting healthy HRV patterns over time ultimately means creating conditions that allow parasympathetic processes to operate more effectively^1,3.

This includes reducing unnecessary sympathetic activation, supporting sleep quality, and, where appropriate, incorporating evidence-based tools designed to modulate autonomic pathways directly^{11,12,13,14,15,16}. Within this broader framework, evidence-based neuromodulation approaches may offer additional support by engaging well-characterised autonomic pathways. Nurosym has been evaluated across a substantial body of clinical research, distinguishing it as a science-aligned option for individuals exploring ways to support parasympathetic regulation as part of a balanced, long-term health routine.

 

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Disclaimer: This article is for educational purposes only and does not provide medical advice. Nurosym is not intended to diagnose, treat, cure, or prevent any disease. Always consult a qualified health professional for personalised guidance.

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