What Is HRV? Understanding your body’s response to stress and recovery

What is heart rate variability?

Heart rate refers to the number of times your heart beats per minute (bpm). Heart rate variability (HRV), on the other hand, measures the variation in time between consecutive heartbeats. So, rather than reflecting how fast the heart beats, HRV indicates how adaptable the cardiovascular and nervous systems are to change and is influenced by a range of factors, including age, physical fitness, genetics, sleep quality, stress, medications, and overall health.

HRV reflects the activity and balance of your autonomic nervous system (ANS), which regulates many of the body's automatic functions. The ANS has two main branches: the sympathetic nervous system ("fight or flight"), which prepares the body to respond to stress, and the parasympathetic nervous system ("rest and digest"), which promotes recovery and relaxation. The interaction between these two systems is reflected in your HRV.

Generally, a higher HRV is associated with greater resilience, better cardiovascular fitness, and a healthier, more responsive nervous system, while a persistently lower-than-usual HRV may indicate chronic stress, fatigue, illness, or reduced recovery capacity. HRV is valuable because it reflects how effectively your body adapts to physical and emotional stressors and how quickly it returns to a balanced state. This adaptability is closely linked to the activity of the vagus nerve, a key component of the parasympathetic nervous system. As a result, HRV can provide useful insight into autonomic nervous system function, recovery, and overall physiological resilience.

As we have mentioned many things can affect your HRV including:

• Age and gender
• Meal timing and nutrition
• Undereating and overeating
• Caffeine
• Smoking and alcohol consumption
• Genetics
• Anxiety and depression
• Bodyweight and inflammation
• Circadian rhythm and sleep
• Time of day
• Health conditions
• Inflammation

(Williams, 2019)

Remember that HRV naturally varies from day to day. Rather than focusing on a single reading, look for trends over time.

What can HRV tell you about stress and recovery?

HRV provides an insight into vagal tone, resilience, adaptability and how the body responds to stress. HRV is also recognised as a useful marker of mental resilience, reflecting your ability to adapt to physical and emotional stressors and recover from them efficiently. (Perna, 2020)

How can you improve your HRV?

Improving your HRV is about supporting your nervous system and helping your body recover effectively from stress.

Exercise regularly - A combination of aerobic exercise and strength training can improve HRV over time. However, avoid overtraining and allow adequate recovery between intense sessions.

Prioritise sleep - Aim for 7–9 hours of good-quality sleep each night. Consistent sleep supports recovery, maintains a healthy circadian rhythm, and is one of the biggest influences on HRV.

Manage stress - Deep breathing, meditation, mindfulness and yoga can activate the parasympathetic nervous system and improve HRV over time.

Spend time in nature - Regular exposure to green spaces has been shown to reduce stress and support nervous system balance.

Limit alcohol - Alcohol can disrupt sleep quality, increase stress on the body and temporarily reduce HRV, even in moderate amounts.

Eat a balanced diet and stay hydrated - A nutrient-rich diet and good hydration support cardiovascular and nervous system health.

Take time to recover - Building rest days, relaxation and enjoyable activities into your routine helps your body return to a balanced state and supports long-term resilience.

Wearables: Is there an emotional impact of tracking health data daily?

Smartwatches and fitness trackers have become part of everyday life, but as these wearable devices become increasingly woven into our daily routines, an important question emerges: what are they doing to our mental and emotional wellbeing? While they promise to help us live healthier lives by tracking things such as HRV, they may also be encouraging us to constantly monitor, measure, and optimise ourselves. We already know the importance of spending less time glued to screens and on social media. Is this level of data tracking empowering us to make healthier choices, or are they creating a new form of anxiety, where every sleep score and missed activity goal becomes another metric to worry about?

Nutrition and HRV

Did you know that what you eat can influence your HRV by affecting nervous system function, inflammation, blood sugar, hydration, and energy production?

Stay hydrated

Hydration is one of the simplest ways to support your body. When you're well hydrated, your blood can more efficiently deliver oxygen and nutrients to your cells, helping your body function optimally. Even mild dehydration can place additional stress on the body, which may negatively affect HRV.

Establish regular eating habits

When you eat can be just as important as what you eat. Irregular meal patterns and frequent late-night eating can disrupt your circadian rhythm, affecting metabolism, sleep quality and recovery. Aim for consistent mealtimes to support your body's natural biological clock.

Eat a plant-rich diet

A diet rich in vegetables, fruit, and whole plant foods provides the vitamins, minerals, and antioxidants needed to support energy production and a healthy nervous system. Research has shown that people with higher intakes of leafy green vegetables and fruit tend to have a higher HRV (Park, 2009; 2020). Vegetarian dietary patterns have also been associated with improved HRV compared with typical Western diets (Fu, 2006).

Prioritise omega-3 fats

Omega-3 fatty acids have been extensively studied for their effects on cardiovascular and nervous system health. They have been shown to improve HRV and enhance vagal tone, a marker of parasympathetic ("rest and digest") nervous system activity (Xin, 2013).

Include omega-3-rich foods such as oily fish (salmon, sardines, mackerel), flaxseeds, chia seeds, hemp seeds and walnuts.

Increase your intake of polyphenols

Polyphenols are naturally occurring plant compounds with potent antioxidant and anti-inflammatory properties that help protect cells from oxidative stress. Foods particularly rich in polyphenols include berries, extra virgin olive oil, green tea, cacao, and dark chocolate.

Support your gut microbiome

Your gut and brain communicate continuously through the gut-brain axis, with the vagus nerve acting as one of the primary communication pathways. A diverse, healthy gut microbiome supports mood, cognitive function, and immune health and, therefore, may positively influence HRV.

Include fermented foods rich in beneficial bacteria, such as kefir, natural yoghurt, sauerkraut, kimchi, and kombucha. Alongside these, consume plenty of prebiotic foods, including onions, garlic, leeks, oats, asparagus, and legumes, to nourish beneficial gut bacteria.

Limit processed foods

Highly processed foods, excess added sugar, alcohol, and smoking can all reduce HRV by increasing inflammation and oxidative stress.

Can supplements improve HRV?

Addressing any nutrient deficiencies and building strong nutritional foundations with a high-quality multivitamin, a well-formulated omega-3 supplement, and, where appropriate, a probiotic can support overall health and may have a positive influence on HRV. From there, supplements can be tailored to your individual needs. For example, if stress is a contributing factor, nutrients such as magnesium and L-theanine, or adaptogenic herbs including ashwagandha or rhodiola, may help support the body's stress response and promote relaxation.

Conclusion

HRV can offer valuable insight into your health, particularly how your body responds and adapts to stress. Supporting your wellbeing through good nutrition, healthy lifestyle habits and appropriate supplementation can help optimise HRV and build resilience.

References

Fu, C. H., Yang, C. C., Lin, C. L., & Kuo, T. B. (2006). Effects of long-term vegetarian diets on cardiovascular autonomic functions in healthy postmenopausal women. The American Journal of Cardiology, 97(3), 380–383.

Park, S. K., Tucker, K. L., O'Neill, M. S., Sparrow, D., Vokonas, P. S., Hu, H., & Schwartz, J. (2009). Fruit, vegetable, and fish consumption and heart rate variability: The Veterans Administration Normative Aging Study. The American Journal of Clinical Nutrition, 89(3), 778–786.

Perna, G., Riva, A., Defillo, A., Sangiorgio, E., Nobile, M., & Caldirola, D. (2020). Heart rate variability: Can it serve as a marker of mental health resilience? Journal of Affective Disorders, 263, 754–761.

Reginato, E., Azzolina, D., Folino, F., Valentini, R., Bendinelli, C., Gafare, C. E., Cainelli, E., Vedovelli, L., Iliceto, S., Gregori, D., & Lorenzoni, G. (2020). Dietary and lifestyle patterns are associated with heart rate variability. Journal of Clinical Medicine, 9(4), Article 1121.

Williams, D. P., Koenig, J., Carnevali, L., Sgoifo, A., Jarczok, M. N., Sternberg, E. M., & Thayer, J. F. (2019). Heart rate variability and inflammation: A meta-analysis of human studies. Brain, Behavior, and Immunity, 80, 219–226.

Xin, W., Wei, W., & Li, X.-Y. (2013). Short-term effects of fish-oil supplementation on heart rate variability in humans: A meta-analysis of randomized controlled trials. The American Journal of Clinical Nutrition, 97(5), 926–935.