Revealed: How hearts of men and women respond differently to stress hormone

It is a universally acknowledged fact that all of our hearts beat fast when we are under a lot of stress, irrespective of our gender. But it is only recently that scientists have found out that the hearts of men and women respond differently to the stress hormone called noradrenaline.  

The study that was published in the journal Science Advances reveals that the brand-new discovery was a result of a lab experiment on mice. No, we aren’t joking. In fact, this research indicated that how the two sexes react different to certain drugs that are prescribed to humans for cardiac concerns such as arrhythmias and cardiac arrests.  

Okay, so here’s how the discovery happened. The team of scientists involved in the study developed a cutting-edge fluorescence imaging system and used it to check how a mouse’s heart reacts to hormones and neurotransmitters in real time. During this, several mice, both male and female were exposed to noradrenaline, that is not only a stress hormone but a neurotransmitter, associated with the body’s fight or flight response.  

The results reveal that initially, both male and female mouse hearts respond uniformly. However, the female heart return to normalcy faster than the male heart. This in turn made the researchers realise that it was the female heart that repolarised, meaning it reset between each heartbeat quicker than the male heart.  

Do you realise what this means? Yes, male hearts are more susceptible to heart diseases like arrythmias. Now, considering the functioning of human hearts are more or less similar to that of mice hearts, it means, the danger of stress hormones affecting men is more than that in women. Maybe that’s why, as per the 2020 statistics of USA, 1 in 4 men die of cardiac ailments as opposed to 1 in 6 women. This means that cardiology research should have a greater focus on human males, although females too should be part of it. It also means that two separate research should be conducted for both the sexes. 

For those unaware, arrythmia is a kind of cardiac disorder wherein electric impulses that control heartbeats do not function properly. On an average, it affects 1.5 to 5 percent of the global population, especially men.