Are heart attacks less dangerous when they occur at night time? New study makes surprising discoveries

Scientists had observed that heart attacks at night time tend to be less threatening than those during daytime.

It has long been observed that heart attacks at night tend to be less damaging than those occurring in daytime. Studies in the past have suggested that neutrophils, the immune cells that act as the first responders to injury, may be responsible for this difference.

Researchers discovered that the mice with depleted neutrophil count suffered less damage when a heart attack was induced in them.(Freepik)

It was estimated that these cells, due to being more aggressive during the daytime, cause more inflammation and collateral damage to tissue in this period. A study published in the Journal of Experimental Medicine on December 12 looked more closely at this phenomenon.

What to know?

Live Science reported that this study looked at the records of more than 2,000 people who suffered a heart attack. It concluded that those who went through this ordeal during the day showed a greater neutrophil count and more damage. This suggests that these neutrophils may be the very cause of damage.

The test was conducted on mice. They were split into two groups with one having a normal neutrophil count and the other a depleted one through an antibody treatment. The researchers found that the mice with depleted neutrophil count suffered less damage when a heart attack was induced in them.

So, now the question arises - Can these results be used to reduce the impact of heart attacks on vulnerable people?

For this, the scientists have to find ways to artificially calm down these immune cells. To achieve this, they are focussing on a receptor in these cells called CXCR4. This receptor calms down neutrophils on receiving signals from the body. Scientists doing the study found that increasing these receptors in the mice reduced the intensity of neutrophils to their nighttime level and thus, lessened their impact on the body.

The focus would now shift to finding medicines that can lessen the intensity of neutrophils without compromising their immunity. This will be a huge advance in medicine.

Can heart attacks occur during sleep?

The only thing scarier than a heart attack is one that occurs during sleep. This is very much a possibility and people need to be careful about it. According to Kailash Healthcare, the body’s circadian rhythm – which controls the body clock in relation to sleeping – leads to a spike in blood pressure between 4 AM and 6 AM. This, along with changes in the heart rate, can sometimes lead to cardiac arrests.

Another danger to cardiovascular health during sleeping is Obstructive Sleep Apnea (OSA), which causes major gaps between breathing. This could lead to low oxygen levels, high blood pressure and an increase in the strain on the heart. This could also trigger a heart attack.

So, while the decreased intensity of neutrophils makes the heart attacks at night less dangerous, these other factors increase the possibility of a heart attack at night.