The heart appears to be more vulnerable to palpitations at a certain time of day.
A cardiac arrhythmia results in a heart that beats too slowly, too quickly or in an anarchic manner. A person who suffers from it may feel palpitations but also shortness of breath or fatigue. This arrhythmia can be caused by alcohol abuse, caffeine, tobacco and certain pathologies such as diabetes, high blood pressure or even thyroid problems. If the arrhythmia originates from the ventricles of the heart, it is said to be ventricular. The ventricles of the heart contract chaotically without pumping blood, as Dr. Stéphane Boulé explained in a previous article: “This is the main mechanism of sudden deaths.” According to one English study published in the journal Traffic Researchcardiac arrhythmias are much more present at a certain time of the day and researchers wanted to understand why.
The research was carried out at Imperial College London on mice. Researchers have discovered that the stress hormone cortisol binds to a specific receptor in heart cells. This receptor influences the genes regulating the ion channels that control the heartbeat. These channels work like switches that turn on and off with the rhythm of day and night. Sometimes, early in the morning, lights can flash unexpectedly and create a disorder in the heart: ventricular arrhythmias. According to researchers, it is because cortisol reaches its maximum level a few minutes before waking up that the heart becomes more vulnerable to arrhythmias. They also showed that injecting a drug that inhibits the cortisol receptor prevents morning changes in ion channels and the risk of arrhythmia.
The discovery of the link between cortisol levels and arrhythmia could open the prospect of new treatments. “Our hearts are actually different organs at different times of the day. They are more vulnerable first thing in the morning due to ancient circadian rhythms, which evolved over millions of years. All species have this in common, so even “While our study involves mice, we believe this applies directly to human and mammalian hearts.”, said Alicia D’Souza, lead researcher of the study. The objective now is to demonstrate similar effects in humans.