Common Causes of Low Heart Rate

Normal heart rate in people is 60-100 beats per minute. But if the heart rate is lower than 60 beats per minute, that may indicate bradycardia development. If the pulse is constantly 30-40 beats per minute and it doesn’t increase even during physical activity, it’s a quite dangerous condition. The symptomless current of bradycardia exacerbates negative process.

Almost all causes of low heart rate are related to pathologies. They are conditionally divided into several categories - cardiology, toxicology, underlying diseases, and physiological factors.

Physiology

• Sleeping at night. During sleep, all processes in our organism slow down: metabolic, endocrine, and digestive. The heart also slows down its rhythm and accordingly the blood circulation decreases. But room temperature (too cold/hot), self-medication with sedatives lead to a decrease in heart rate.
• Being in low-temperature conditions. The lower the ambient temperature, the lower the pulse. Our organism goes into “safe mode” - gaining weight. And it’s not about hypothermia or the frostbite, which are pathological processes. Change of seasons or moving to a colder area impact the function of the heart. A human’s pulse may be 50-40 beats per minute in such conditions, but it will not negatively affect your health.
• Hormonal imbalance in adolescence. Irregular pulse is a normal thing for teenagers. It’s related to changes in the organism. The growth of bones, muscles, and organs, changes in work of the organism system make the heart beat faster. That’s why irregular pulse is not an abnormal process, but it should be under control.
• Sports. Most athletes have athletic heart syndrome. It’s a non-pathological condition, in which the human heart is enlarged, and the resting heart rate is lower than normal.  

Cardiology

• Ischemia - a condition caused by a restriction in blood supply to tissues, organs, and heart, leads to metabolic dysfunctions. Low heart rate is one of the symptoms of ischemia.
• Myocardial infarction is damage of the heart muscle, caused by decreasing blood flow to a part of the heart. Symptoms of infarction are acute chest pain, weakness, hyperhidrosis, pulse lower than 30-40 beats per minute.
• Heart failure - is a chronic disease, may be symptomless. Heart pump function worsens and heart rate levels are lower than normal.
• Cardiomyopathy. Is a group of diseases connected with changes in heart tissues - muscles, vessels, aorta, and heart valves. Blood circulation slows down and heart rate becomes lower.
• Myocarditis is a condition accompanied by inflammatory processes in heart muscle, caused by infectious diseases, autoimmune diseases, intoxication. Heart rate may be lower than 40 beats per minute.
• Congenital and acquired anomalies of the heart. The pulse may be critically low in cases of anomalies of the heart.

Toxicology

• Acute intoxication of the organism. Occurs in cases of consumption of rotten or dangerous food, for example, mushrooms, and long term cancer treatment.
• Excessive consumption of medications, including diuretics, heart stimulators. Self-medication, changes in compliance of medication, lead to intoxication.
• Deficiency or excess of magnesium, potassium, sodium in the organism negatively affects the heart. It may lead to a low heart rate.
• Diets. If the diet excludes proteins, fats or carbs, it may cause metabolism dysfunction and weakness of heart. Lack of food intake leads to oxygen starvation of tissues. A low pulse is the first sign of heart anomaly.
• Smoking, drug and alcohol abuse. These bad habits will destroy heart functioning later or sooner. In these cases, a low pulse is also an early symptom of heart problems.

Underlying diseases

These underlying diseases may include low heart rate:

• Dysautonomia;
• Anemia;
• Respiratory diseases - bronchitis, asthma;
• Acute infectious diseases - hepatitis, diphtheria, typhoid fever, meningitis;
• Endocrine diseases - diabetes, thyroid dysfunction, dysfunction of adrenal glands;

A low heart rate is always a serious reason to check the health, especially heart condition. Even if it’s not constant, it doesn’t mean you can ignore it. In any case, you need to consult with a doctor to find the problem causing low pulse.