What is the optimal method to increase nighttime Heart Rate Variability (HRV)?

From the Guidelines

To increase nighttime heart rate variability (HRV), establishing a consistent sleep schedule and practicing stress management techniques are crucial. This approach is supported by the most recent evidence from 2025, which emphasizes the importance of sleep quality and autonomic nervous system function in determining HRV 1.

Key Recommendations

• Establish a regular sleep schedule, aiming for 7-9 hours of quality sleep each night, as this has been shown to positively impact HRV 1.
• Avoid alcohol, caffeine, and heavy meals within 3-4 hours of bedtime, as these can disrupt autonomic nervous system function and reduce HRV 1.
• Engage in regular moderate exercise, particularly earlier in the day, to improve nighttime HRV, but avoid intense workouts close to bedtime, which can have a negative impact on sleep quality and HRV 1.
• Practice relaxation techniques such as deep breathing, meditation, or gentle yoga before sleep to activate the parasympathetic nervous system and promote higher HRV measurements during sleep 1.
• Maintain good sleep hygiene by keeping the bedroom cool (65-68°F), dark, and quiet, and consider supplementation with magnesium (200-400mg) or omega-3 fatty acids, which may support autonomic function and improve HRV 1.

Additional Considerations

• Stay well-hydrated throughout the day but reduce fluid intake before bed to minimize disruptions to sleep and HRV 1.
• Select a wearable device with a high sampling rate to accurately measure nocturnal HR and HRV, and use 2-h rolling averages for the duration of reported bedtime to ensure reliable data 1.
• Report physical activity throughout the days of nocturnal HR measurement and document bedtime to control for potential confounding variables 1. By following these recommendations and considering the additional factors that influence nighttime HRV, individuals can take a proactive approach to improving their HRV and overall health outcomes.

From the Research

Increasing Nighttime HRV

To increase nighttime Heart Rate Variability (HRV), several techniques have been studied, including:

• Progressive Muscle Relaxation (PMR)
• Breathing exercises, such as voluntary slow breathing and diaphragmatic deep breathing
• Cognitive behavioural intervention combined with breathing relaxation exercise

Techniques for Increasing HRV

The following techniques have been shown to increase HRV:

• PMR: significantly increased HRV compared to an active control group 2
• Breathing exercises:
  • Voluntary slow breathing: increased vagally-mediated HRV during, immediately after, and after a multi-session intervention 3
  • Diaphragmatic deep breathing: decreased systolic and diastolic blood pressures, reduced heart rate, and reduced anxiety in hypertensive or prehypertensive individuals 4
• Cognitive behavioural intervention combined with breathing relaxation exercise: improved sleep quality and HRV in patients with major depression 5

Recommendations for Increasing Nighttime HRV

Based on the studies, the following recommendations can be made:

• Practice PMR three times a week for 20 minutes 2
• Engage in voluntary slow breathing exercises, with a frequency of less than 10 breaths per minute 3
• Practice diaphragmatic deep breathing exercises at less than 6 breaths per minute for 10 minutes, twice a day, for 4 weeks 4
• Consider combining breathing exercises with cognitive behavioural intervention for improved sleep quality and HRV 5