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How quickly your heart rate returns to normal after exercise can reveal surprising information about your overall health.
If your heart pounds when climbing stairs or you are short of breath when jogging to catch the bus, this may indicate low physical fitness.
However, what happens at the end of physical activity is just as revealing about the internal functioning of the body.
Regarding this, the heart rate recovery test (HRC) becomes relevant, defined as the difference between the heart rate during the maximum effort and the rhythm recorded one minute after finishing.
Nieca Golderberg, a cardiologist at New York University Grossman School of Medicine, explains that CFR is a good indicator of cardiovascular health and predicts high blood pressure and cardiac events.
Still, the RFC covers much more. A poor result acts as an early warning signal for hidden problems in the body, crucially including the overall risk of mortality.
In 1999, scientists at the Cleveland Clinic (Ohio) published striking results after evaluating the CFR of 2,400 adults and following them for six years.
The team found that people with low cardiac recovery were four times more likely to die during the study period.
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Other research groups around the world have obtained similar results.
CFR has established itself as a strong predictor of death from any cause, regardless of the existence of apparent cardiac problems.
In young and middle-aged adults, CFR shows a stronger association with mortality risk than high blood pressure.
Here's a simple way to calculate your RFC with things you probably already have at home.
How to calculate frequency
It is essential to consult your doctor before starting a new exercise program.
If dizziness, pain or tightness in the chest, or shortness of breath that is disproportionate to the effort made, appear, the activity should be stopped immediately.
This test is not suitable for people with pre-existing heart conditions without medical supervision.
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The first step is to have a method of recording data and a stopwatch (available on most mobile phones).
Using a smartwatch or activity tracker makes the process easier.
The maximum heart rate is then calculated. Smart devices display this information automatically; Otherwise, the estimated value can be obtained by subtracting the current age from 220.
Subsequently, an exercise session is performed with sufficient intensity to raise the heart rate to between 70% and 85% of the maximum.
Possible activities include running, cycling or rowing, depending on one's physical condition.
To calculate the CHR, the pulse is measured immediately at the end of the exercise, at which time it reaches its maximum point. Using a smart watch simplifies this measurement.
Another alternative is to place a finger on your neck and count the heartbeats for ten seconds, then multiply that number by six to obtain the approximate beats per minute.
Finally, you rest for one minute in a sitting or lying position to take your pulse again.
The difference between both figures is the RFC.
The ideal RFC
The body requires the heart rate to drop quickly after finishing exercise. Optimal recovery involves a drop of at least 18 beats during the first minute.
This value varies from person to person and depends on factors such as age. However, a record of less than 12 heartbeats may indicate risks of future health problems.
A warning sign
The relationship between CFR and mortality risk is linked to the vagus nerve.
This main nerve connects the brain to the rest of the body and transmits signals to and from the heart, liver, intestines, and other organs.
Its function regulates the transition between the state of alert (fight or flight) and the state of relaxation (rest and digestion).
Lindsay Bottoms, professor of Exercise and Health Sciences at the University of Hertfordshire (United Kingdom), points out the existence of two systems with the functions of accelerator and brake on the heart.
During exercise, the sympathetic nervous system acts as an accelerator and activates fight or flight mode. As a result, the heart rate speeds up and blood vessels dilate to pump oxygen to the muscles.
When you stop training, the body needs to eliminate accumulated metabolic waste, such as lactic acid, an oxygen-dependent process.
Bottoms indicates that this demand requires maintaining blood flow and elevated heart rate.
Once the cleaning is complete, the body applies the brakes and activates the parasympathetic mode, corresponding to the state of rest and digestion.
Increasing physical fitness improves the body's ability to alternate between both states.
This phenomenon, called elevated vagal tone, provides multiple benefits, such as better mental and cognitive health, a stronger immune system, and a reduction in inflammation and mortality risk.
How to improve the RFC
With concerns about CFR values, Golderberg advises scheduling a doctor's visit for a complete cardiac risk assessment.
The good news is that the problems detected are not definitive. Research shows that exercise programs improve CHR and return mortality risk to normal levels.
Bottoms and Golderberg recommend regular cardiovascular exercise to keep the system in optimal condition. Golderberg suggests activities such as walking at a moderate pace, cycling, running, swimming or dancing.
*This article provides general information only and is never a substitute for professional medical judgment.
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