Heart Rate Variability (HRV) refers to the variation in time intervals between consecutive heartbeats. It is a measure of the autonomic nervous system's regulation of the heart, reflecting how well the body can adapt to stress and environmental changes. Higher HRV is often associated with better cardiovascular fitness and resilience, while lower HRV may indicate stress or potential health issues. HRV can be influenced by various factors, including exercise, sleep quality, stress levels, and overall health. Monitoring HRV can provide insights into an individual's well-being and help in managing conditions like anxiety and depression.