Resting heart rate

# What is the resting heart rate? Resting heart rate is an important physiological parameter that reflects the number of heart beats per minute when a person is at rest. It is widely recognized as an indicator of cardiovascular health and overall fitness. Understanding the factors that influence resting heart rate, their impact on health and their measurement methods are essential for both clinical practice and research. # Normal range and measurement The normal range for resting heart rate varies according to age, gender and fitness level. For adults, it is between 60 and 100 beats per minute (bpm). However, athletes and people with a high level of cardiovascular fitness often have lower resting heart rates, sometimes as low as 40 beats per minute. The resting heart rate is usually measured after a period of rest, ideally in the morning before any physical activity, using a heart rate monitor or by manually palpating the pulse. # Influencing Factors The resting heart rate is influenced by a variety of physiological factors. The autonomic nervous system plays a decisive role, with the balance between sympathetic and parasympathetic activity determining the heart rate. Increased sympathetic activity, associated with stress or physical exertion, leads to an increase in heart rate, while increased parasympathetic activity, characteristic of relaxation, leads to a decrease in heart rate. Endocrine factors are also relevant, as hormones such as adrenaline (the stress hormone) and thyroxine (the thyroid hormone) can influence heart rate. In addition, intrinsic heart rate, which is determined by genetics, plays a role in determining an individual's resting heart rate. > ## Good to know > > Genes that influence our sleep-wake rhythm and stress can also change our resting heart rate. # Other influencing factors - Age: Resting heart rate tends to increase with age as parasympathetic tone decreases and the cardiovascular system changes. - Physical fitness: Regular physical activity improves cardiovascular efficiency and leads to a lower resting heart rate. Endurance training in particular is associated with a significant reduction. - Lifestyle factors: Smoking, stress and poor diet can increase resting heart rate, while a healthy diet, stress management and quitting smoking are associated with a lower resting heart rate. - Medical conditions: Conditions such as hyperthyroidism, anemia and cardiovascular disease can increase resting heart rate. However, it can also be lowered by beta-blockers and other medications. # Clinical significance Resting heart rate is a valuable predictor of cardiovascular morbidity and mortality. An elevated resting heart rate is associated with an increased risk of cardiovascular events. It is an independent risk factor for these diseases, even when other variables such as blood pressure and cholesterol levels are taken into account. # What does genetics have to do with it? In your analysis, several genes associated with the resting heart rate were examined. You can read about the most important ones here: The SNP rs9398652 is located in the GJA1 gene, which codes for connexin 43 (Cx43). Cx43 is critical for gap junctions in heart tissue that enable cell communication and support synchronized contraction of the heart muscle. Variations in GJA1, including rs9398652, can impair the function of these channels, which can alter the heart's electrical conduction system and affect resting heart rate. Disruptions in GJA1 can lead to arrhythmias and affect heart rate regulation, manifested by an increased resting heart rate. The SNP rs365990 is found in the MYH6 gene. This gene codes for the subunit of the heavy alpha chain of cardiac myosin, a protein that is crucial for the contraction of the heart muscle. Variations in MYH6 can influence the contractility of the heart and thus the resting heart rate. Studies have shown that genetic variations in MYH6 are associated with differences in heart rate and susceptibility to atrial fibrillation. rs145669495 is located on the CSMD1 (CUB and Sushi Multiple Domains 1) gene. The CSMD1 gene is known to play a role in regulating the complement system and is involved in neuronal development and synaptic function. CSMD1 is expressed in various tissues, including the heart, indicating its potential influence on cardiovascular traits. The role of CSMD1 in regulating the complement system, part of the immune response, suggests that genetic variations may influence inflammatory processes in cardiac tissue. Chronic inflammation impairs cardiac function and RHR could thus be altered. Since CSMD1 is involved in neuronal development, the SNP rs145669495 may influence the autonomic regulation of heart rate. The autonomic nervous system controls the balance between sympathetic and parasympathetic activity, which has a direct effect on RHR. The SNPs rs142916219 and rs755291044 are located on the ASPH gene (aspartate beta-hydroxylase). The ASPH gene encodes an enzyme involved in post-translational modification, particularly hydroxylation, which is critical for cell differentiation and tissue development. This gene is expressed in various tissues, including the heart. Variations in ASPH can alter the activity of the enzyme and affect cellular processes in cardiac tissue. This can lead to changes in heart muscle function and consequently affect the heart rate. ASPH is also involved in signaling pathways that regulate calcium ion concentration in cells. Calcium signaling is crucial for the contraction and relaxation cycles of the heart muscle. Therefore, genetic variations that affect the function of ASPH can disrupt these processes, potentially leading to changes in heart rate. The ASPH gene also plays a role in the development and maintenance of heart tissue. The genetic variations rs142916219 and rs755291044 can affect the structural and functional integrity of the heart and thus indirectly influence the heart rate at rest.