Your heart plays a crucial role in your body. It is a muscle in the center of your circulation system which pumps blood around your body with every beat. This blood sends oxygen and nutrients to all parts of your body, and carries away unwanted carbon dioxide and waste products. Any impairments can lead to cardiovascular diseases.
Conditions of the heart and the circulation system – also called cardiovascular diseases (CVDs) – are a group of disorders which includes, in particular, coronary heart disease, cerebrovascular disease, and rheumatic heart disease. They are the leading cause of death globally. According to the World Health Organization (WHO), they cause an estimated 17.9 million deaths each year. More than four out of five CVD deaths are due to heart attacks and strokes, and one third of these deaths occur in people under 70 years of age. Most important behavioral risk factors are an unhealthy diet, physical inactivity, tobacco use, and harmful use of alcohol. Effects show up in individuals as raised blood pressure, raised blood glucose, raised blood lipids, and overweight and obesity.
The cardiovascular and the respiratory system exist in close vicinity to each other. Breathing directly affects the cardiovascular system. In turn, one of the main symptoms of congestive heart failure is shortness of breath. Cardiopulmonary exercise is one of the best things an individual can do to promote cardiovascular health: The pressure generated by breathing and expanding the lungs influences the volumes and pressures in the chambers of the heart and blood vessels. These changes stimulate sensory nerves that influence the autonomic nervous system (ANS) and the rate and depth of breathing. The pattern generators in the brainstem that drive and regulate heart rate, blood pressure, and breathing are also closely aligned. With exercise, a “central command” from higher brain centers accelerates the activity of both systems, and sends feed‐forward signals to the brain stem in preparation for the increased metabolic demands of exercise.
Where heart rate variability comes in
The analysis of fluctuation in intervals between heartbeats provides important information related to the autonomic modulation of heart rate variability (HRV).
HRV parameters are considered predictors of morbidity and mortality, and researchers have pointed towards a close relationship between cardiovascular fitness and HRV. While HRV is often impaired in patients with cardiovascular and metabolic diseases, researchers found this relationship to be more pronounced in patients with cardiovascular and metabolic diseases and in aging. This became manifest, in particular, in individuals whose cardiovascular fitness and HRV were below the predicted values for the respective age and gender. Women in reproductive age as well as age-matched men show distinct regulations in cardiac autonomic modulation; and aerobic exercise was one type of training which appeared to attenuate any autonomic impairments.
And in the Journal of the American Heart Association (JAHA), Craighead et al investigated the effect of high‐resistance inspiratory muscle strength training on blood pressure, endothelial function, and arterial stiffness in older adults with mildly elevated systolic blood pressure. For that age group, their double‐blind, randomized, sham‐controlled trial showed that this type of exercise can improve control of blood pressure as well as increase HRV.
Modern technology enables patients to use their smartphones for measuring HRV and pulse rate. To combine this biofeedback data with, e.g. breathing exercises is a simple and cost-effective way to take control of body functions. Patients will typically conduct these trainings in a setting with professional support. In the case of CVD, training accompanied by HRV measurement can help to prevent cardiovascular issues, to detect developing conditions for early intervention, and to monitor effects of treatment.