Is there a finite number of heartbeats for each person?

"The heart does not work like a 'countdown' for heartbeats, and there is no fixed number of heartbeats throughout a lifetime ," answers clearly and without hesitation someone who knows very well what he is talking about, Dr. Luis Rodríguez Padial , president of the Spanish Society of Cardiology (SEC).

From a medical perspective, it has never been proven that each person's heart is predestined to beat a certain number of times . This, on the other hand, would be equivalent to saying that we come into this world with a specific "expiration date" that's known from birth.

This idea isn't a crazy, spontaneous idea that came out of nowhere. Its origin is based on the knowledge and comparison of the different heart rates among different animal species. It has been proven that animals with fast metabolisms, such as mice, have extremely high heart rates and short lifespans. Specifically, the heart of rodents beats between 500 and 700 times per minute at rest . This means that in a single day, it can accumulate more than 700,000 beats, and in its lifespan, which is usually two to three years, it reaches about a billion beats in total.

On the opposite side of this quadrilateral, we find the animals with the slowest hearts, such as elephants. These mammals have a much slower heart rate . So much so that they only count between 25 and 35 beats per minute at rest, which translates to 40,000 beats a day. And since they live between 60 and 70 years, they also reach about a billion beats throughout their life.

The curious thing about this case is that, although mice and elephants have radically different vital rhythms , the total number of heartbeats throughout their lives ends up being very similar.

The (inconsistent) rate of life theory

Between the hearts of rodents and pachyderms , the human heart beats on average about 60 to 100 times per minute at rest . If you calculate this, that's equivalent to between 2.5 and 3.5 billion heartbeats over a lifespan of 80 years.

The discovery of these calculations assigned to each species led to the formulation of a biological hypothesis at the beginning of the 20th century, the rate-of-life theory . This proposes that each organism has a limited amount of "vital energy" throughout its existence, which would mean that the faster this energy is consumed (more heartbeats ), the shorter the life span.

However, this theory doesn't hold up. Over time, science has demonstrated various aspects that debunk the idea that a high heart rate is inevitably associated with premature death. For example, it is known that, in humans, physical exercise increases energy expenditure, and this, far from shortening life, is associated with greater longevity. Therefore, a long life does not appear to be a direct consequence of having "regulated" the number of beats assigned to our hearts.

Furthermore, a heart with a low resting heart rate ( something very common in athletes ) is associated with “ greater longevity and lower cardiovascular risk, while a high heart rate is associated with higher mortality and cardiovascular events, especially in older adults,” the expert points out.

Heart rate and longevity

Between a fast heart and a slower one, the best is one that stays within a specific heart rate range. "In healthy adults, a resting heart rate between 60-70 bpm is associated with a lower risk of mortality and cardiovascular events," says Rodríguez. Meanwhile, " rates persistently above 80-85 bpm are linked to a higher risk ." "However," warns the expert, "a mild tachycardia (100 bpm) at rest is a risk marker."

Therefore, "from a health perspective, persistent tachycardia is more dangerous than physiological bradycardia , unless the bradycardia causes symptoms or is associated with structural disease," he concludes.

A strong heart lengthens life

The clearest conclusion about the relationship between longevity and heart rate is that this link "is multifactorial." This is the opinion of the SEC president, who also emphasizes the importance of maintaining a healthy heart to maintain a "young" heart, advising people to adopt habits such as regular physical activity, monitoring blood pressure and lipids, eating a healthy diet rich in vegetables, low in salt and saturated fats, avoiding smoking and stress, and maintaining a healthy body weight.

In the face of the habits he recommends integrating into daily life, the doctor lists the main factors that damage the heart: hypertension , smoking, sedentary lifestyle, obesity, dyslipidemia, diabetes and persistent tachycardia.

However, no matter how hard we try to take care of our heart , the passage of time always takes its toll. However, it doesn't always do so in the same way, nor do its effects appear at the same age, as it is "a gradual process that depends on genetic and environmental factors."

On the other hand, beyond the timing and intensity with which the effects of time manifest on the heart, all people share the same signs of cardiac aging , which usually appear from middle age onwards. Among them, the cardiologist highlights "decreased exercise tolerance, arrhythmias , dyspnea, and fatigue. In addition, functionally, lower heart rate variability and increased vascular stiffness are observed."