Daylight Saving Time (DST) is a practice that's been around for a long time where the clocks are set forward by an hour in the spring and then set back an hour in the fall.

It was introduced as a way to save energy and make the most of daylight hours. But over the years, there has been a lot of debate about the effect it has on our health, particularly the risk of heart attacks.

Our bodies have an internal clock called the circadian rhythm that controls our sleep-wake cycle and other bodily functions. When the time changes due to daylight savings time, it disrupts this internal clock, and we have to adjust to the new schedule. This can lead to a range of health problems.

The science is clear that daylight time and its associated clock changes are causing serious harm to our health, sleep researchers say. Numerous studies have highlighted a spike in heart attacks, strokes and traffic crashes that occur the day after clocks move forward, as well as longer-term mental and physical health risks. As a result, some jurisdictions in the U.S. and Canada are considering get rid of daylight savings time altogether. 

Heart Attacks & Strokes the First Monday After  

Research has shown that the rate of heart attacks increases in the days following the spring DST transition. The American Heart Association cites studies showing increase in heart disease, stroke incidents associated with change to daylight saving time.

“We don’t really know the specific reason for increases in heart disease and stroke during the daylight saving time change, but it likely has something to do with the disruption to the body's internal clock, or its circadian rhythm,” said American Heart Association President Donald M. Lloyd-Jones, M.D., Sc.M., FAHA.

“The best preparation for the time change is to make gradual lifestyle improvements year-round. Move more. Get your cholesterol and blood pressure checked. Make sure you’re working on healthy sleep habits and eating smart”.

“These healthy lifestyle behaviors won’t only soften the annual biological clock shock, they are proven ways to reduce your risk of heart disease and stroke, helping you live a longer, healthier life,” he said.

A study published in the New England Journal of Medicine ^1 2 found that the rate of heart attacks increased by 24% on the Monday following the spring daylight savings transition, compared to the average rate of heart attacks on other Mondays throughout the year. The study also found that the rate of heart attacks decreased by 21% on the Tuesday following the fall DST transition, when people gained an extra hour of sleep.  

In a study from Finland ³, researchers found that the overall rate of ischemic stroke was 8% percent higher during the first two days after a daylight-saving time transition.

There are several theories why daylight savings can increase the risk of heart attacks. One theory is that the disruption to the circadian rhythm can cause a decrease in the quality and quantity of sleep, which can lead to an increase in stress hormones and inflammation, both of which can increase the risk of heart attacks.

Another theory is that the sudden change in daylight hours can disrupt the body's natural melatonin production, which can affect blood pressure regulation and increase the risk of heart attacks.

The disruption caused by daylight savings can also affect other factors that can increase the risk of heart attacks, such as blood pressure, heart rate, and the tendency for blood to clot.

People who already have underlying chronic health conditions, such as heart disease and diabetes, are more susceptible to the negative effects of daylight savings. Additionally, people who have difficulty adjusting to changes in their sleep schedule, such as shift workers and people with sleep disorders, are also more likely to be affected.

Insulin Resistance

Insulin resistance is the root cause of metabolic disorders, as it occurs when cells in the body become resistant to the effects of insulin, a hormone that helps regulate blood sugar levels. This condition is a well-known precursor to cardiometabolic health issues, which is a group of interrelated conditions that include cardiovascular disease, type 2 diabetes, and obesity.

Insulin resistance is associated with abnormal glucose metabolism, chronic inflammation, which can lead to the development of atherosclerosis, hypertension, and other risk factors for cardiometabolic health. Insulin resistance can impair the function of the endothelium, which is the inner lining of blood vessels, leading to the dysfunction of the vasculature and an increased risk of heart disease. Therefore, managing insulin resistance is crucial to maintaining cardiometabolic health and reducing the risk of developing serious chronic diseases.

According to Tuffs University research, 93% of the U.S. adult population does not have cardiometabolic health. Cardiometabolic health includes several risk factors including type 2 diabetes and insulin resistance, cardiovascular disease, cholesterol levels, high blood pressure, and overweight and obesity.

For those who find themselves in the 93% of the population, they are vulnerable to the impacts of daylight savings time and therefore at risk for heart attacks and strokes. 

The good news is that insulin resistance can be reversed with lifestyle changes such as eating a healthy diet, exercising regularly, and reducing stress. By making these lifestyle changes combined with the Feel Great System you can improve your body's sensitivity to insulin and reduce the risk of developing insulin resistance.

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