HRV, or Heart rate variability, refers to the time variation between heartbeats. That variation starts from the effect of the ANS or autonomic nervous system on the heart. The autonomic nervous system is the component of our nervous system that regulates the reflex functions of the body. This system has two branches:
- the sympathetic branch (activated during stress or the flight or fight mode)
- the parasympathetic branch (activated during relaxation)
Heart rate variability represents the balance between the two above branches. For example, if you have a low HRV, it indicates that the fight-or-flight mode is overactivated. Anything that disrupts the balance between the two branches causes low HRV.
Unfortunately, it could also lead to increased heart disease and death risk. So does getting a vaccine impact HRC? Yes, it can, but in some people. Increased inflammation levels due to the activation of our immune system may cause a temporary imbalance in the autonomic innervation of the heart after getting a vaccine. A low HRV reflects this imbalance. However, most individuals won’t experience any significant change in HRV after they receive a vaccination shot. Increased vaccination refusal rates (up to 25%) led to unrest about the security of the most recent and quickly manufactured vaccines. Publicizing evidence-based safety and raising public awareness can help people get the Covid-19 vaccine to protect their health. A new systematic review has been published in the MDPI journal Vaccines to study this effect. The report concludes that while there can be some changes in the HRV values after receiving the Covid-19 vaccine, the abnormalities are transient and return to normal after three days of the shot.
The WHO (World Health Organization) database on the adverse events of the COVID-19 vaccination reveals that the vaccine may result in transient neurological symptoms. Some of these effects include parosmia, lethargy, headache, and migraine. There have been a few instances of COVID-19 vaccination-induced ANS dysfunction, even though they are infrequent. HRV is an influential and trustworthy signal for assessing how autonomic balance is regulated. Additionally, based on HRV data, a relationship between influenza vaccine and ANS dysfunction has been discovered.
The South Korean authors who wrote the systematic review reflected on how COVID-19 immunization may impact human HRV-related parameters to support COVID-19 vaccination with data. They reviewed studies that involved a brief decline in the RMSSD value after the Covid-19 vaccine. This drop could be due to the adverse effects of the vaccine. However, for asymptomatic participants, the post-vaccination HRV variations were inconsistent. Other studies revealed that various vaccinations and dosages have varying effects on HRV readings. For example, in contrast to the Johnson & Johnson vaccination, the second shots of the Pfizer-BioNTech and Moderna vaccines may lead to SARS-CoV-2-receptor binding domain (RBD) antibody responses. AstraZeneca’s immunization had a more significant impact on HRV-related changes after the first dose than after the second. After the second doses of the Moderna and Pfizer immunizations, more noticeable alterations in HRV were observed than after the first doses of both vaccinations. Comparatively, the Pfizer-BioNTech vaccine’s third booster dosage had a more significant impact than its initial dose on HRV-based stress indices.
COVID-19 vaccinations significantly more impacted women’s RMSSD than men’s, and younger patients had more severe side effects than older patients experienced. Therefore, we should not avoid the COVID-19 vaccine since the side effects are typically relatively transient. However, the NHS and CDC strongly recommend getting the vaccine as soon as possible. Some people are very conscious of what they put inside their bodies. Thus the COVID-19 vaccine’s contents might worry them, resulting in anxiety and stress. When they consider vaccinating, they may consider it a contaminant. That’s why most people are hesitant or even adamant about skipping the Covid-19 vaccination shot. However, conspiracy theories can also result in changing an individual’s mindset. But we can’t deny that the Covid-19 vaccinations have saved millions of lives. Vaccines played a critical role in helping people resume their personal and professional responsibilities globally. That’s why an individual who doubts the potential side effects of the Covid-19 vaccine should consult their doctor to prepare to manage their adverse effects after the vaccine.