Heart rate variability (HRV), the beat-to-beat variation in either heart rate or the duration of
the R–R interval–the heart period, has become a popular clinical and investigational tool …

The cardiorespiratory system exhibits oscillations from a range of sources. One of the most
studied oscillations is heart rate variability, which is thought to be beneficial and can serve …

An abnormal respiratory rate is often the earliest sign of critical illness. A reliable estimate of
respiratory rate is vital in the application of remote telemonitoring systems, which may …

Cardiorespiratory coupling is an encompassing term describing more than the well-
recognized influences of respiration on heart rate and blood pressure. Our data indicate that …

Key points• Respiratory sinus arrhythmia (RSA) is the variation of heart rate with breathing:
heart rate increases during inspiration and decreases during expiration.• RSA is seen in …

Much of biology is rhythmical and comprises oscillators that can couple. These have
optimized energy efficiency and have been preserved during evolution. The respiratory and …

Key points Cardiac vagal tone is a strong predictor of health, although its central origins are
unknown. Respiratory‐linked fluctuations in cardiac vagal tone give rise to respiratory sinus …

Resting high‐frequency heart rate variability (HF‐HRV) relates to cardiac vagal control and
predicts individual differences in health and longevity, but its functional neural correlates are …

Heart rate variability (HRV) has prognostic and diagnostic potential, however, the
mechanisms behind respiratory sinus arrhythmia (RSA), a main short-term HRV, are still not …

Non‐technical summary The brain controls the heart through parasympathetic (vagal) and
sympathetic nerves. Vagal control is integral to cardiac health and a loss of vagal tone is a …