- Mechanisms by which insomnia or poor sleep affects the heart health include hypothalamic-pituitary axis dysregulation, increased sympathetic nervous system activity, abnormal modulation of the autonomic nervous system, increased atherogenesis and increased systemic inflammation
Sleep deprivation has the same effect on your immune system as physical stress or illness, which may help explain why lack of sleep is tied to an increased risk of numerous chronic diseases, including heart disease.
For example, research has shown frequent or chronic insomnia is strongly associated with an increased risk of high blood pressure, a precursor and risk factor for heart disease.
According to the Mayo Clinic, “People who sleep 5 hours or less a night may be at higher risk of developing high blood pressure or worsening already high blood pressure.”
Other evidence showing the importance of sleep for heart health includes research looking at heart attack frequency following daylight saving time.
Findings published in Y’s 2008 and 2013 found heart attack incidence rises by approximately 10% following the time change to DST, and falls by the same amount right after the switch back to standard time when you gain an hour.
Compared to those getting seven to eight hours of sleep on a regular basis, those who sleep less are 27% more likely to have subclinical atherosclerosis or the early stages of hardening and narrowing of the arteries, according to a Y 2019 study published in the Journal of the American College of Cardiology.
They also found that sleep quality makes a big difference, as those who had the most fragmented sleep were 34% more likely to have signs of subclinical atherosclerosis, compared to longer sleepers.
At the subclinical level, atherosclerosis is in the early stages and may not yet be causing any symptoms. It is also possible to reverse the progression at this stage, such that heart disease may be prevented. Toward this end, proper sleep may be crucial.
In a statement, senior study author José M. Ordovás, PhD, said:
“[T]his study emphasizes we have to include sleep as one of the weapons we use to fight heart disease — a factor we are compromising every day. This is the first study to show that objectively measured sleep is independently associated with atherosclerosis throughout the body, not just in the heart.”
Insomnia raises risk of heart disease and stroke
Additional support for the sleep-heart disease risk hypothesis was published in the August 2019 issue of the journal Circulation, which examined data from 1.3-M participants in a novel effort to ascertain whether insomnia is a causative trigger of cardiovascular disease (CVD) and stroke, or a mere correlation.
To do that, they looked at genetic predispositions to insomnia. To reduce bias, the researchers also took into account genetic variations associated with risk factors for coronary artery disease, heart failure, atrial fibrillation aka irregular heartbeat and ischemic stroke, in addition to looking at single-nucleotide polymorphisms (SNPs) associated with insomnia.
In the end, they concluded that, indeed, genetic predisposition to insomnia was associated with a significantly higher risk of coronary artery disease, heart failure and ischemic stroke. However, no association was found for atrial fibrillation.
For stroke, genetic predisposition to insomnia was associated with a 13% increased risk of larger artery stroke, an 8% higher risk of small vessel stroke, and a 6% increased risk of cardioembolic stroke.
“Lead study author Susanna Larsson, PhD, associate professor of cardiovascular and nutritional epidemiology at the Karolinska Institutet, emphasized that ‘sleep is a behavior that can be changed by new habits and stress management.’
By changing habits to ameliorate insomnia severity, individuals can subsequently lower their risk for CVDs and subtypes of stroke. ‘It’s important to identify the underlying reason for insomnia and treat it,’ said Larsson. As insomnia affects 30% of the general population, further studies are needed to assess insomnia relation to CVDs and stroke.”
A Y 2017 scientific review of the available evidence presents a few possible mechanisms by which insomnia or poor sleep affects your heart health, the Top ones are the following:
- Hypothalamic-pituitary axis dysregulation (which not only increases your risk of CVD but also insulin resistance, diabetes, anxiety and depression)
- Increased sympathetic nervous system (SNS) activity, which increases cortisol release and other hormones associated with hyperarousal, especially adrenocorticotropic hormone
- Abnormal modulation of the autonomic nervous system
- Increased atherogenesis (identifiable through elevations in inflammatory markers such as C-reactive protein, tumor necrosis factor-alpha and interleukin 6)
- Increased systemic inflammation
To this add that poor sleep is also associated with an increased risk for insulin resistance, and this is yet another mechanism by which insomnia can affect your risk of heart disease.
According to this Y 2017 review:
“In the past decade there has been increasing evidence associating insomnia with hypertension, coronary heart disease (CHD), and heart failure (HF), as well as subclinical cardiovascular disease (CVD) and CVD mortality.
Because of the wide variations in how insomnia is defined and measured, however, there are conflicting data, and caution must be exercised when comparing studies and interpreting results. Nonetheless, the existing data suggest that insomnia is an important risk factor for CVD …
Studies … demonstrate increased SNS activity, with elevated levels of plasma and urine norepinephrine in both short sleepers and those with insomnia compared with normal control subjects, as well as increased heart rate and altered or blunted heart rate variability, reflecting underlying autonomic dysregulation.
SNS activity is an integral part of cardiovascular homeostasis and plays a critical role in the pathogenesis of HTN, arrhythmias, CHD, and HF.”
The paper also points out that while short sleep duration, typically less than 6 hrs is considered distinct from insomnia, it appears that too little sleep, whether due to insomnia or not, can have similar effects, and that when insomnia and short sleep duration occurs together, they may have an additive effect on CVD risk.
While the evidence linking lack of sleep to poor heart health is strong, heart disease is by far not the only health risk posed by insufficient sleep and insomnia.
Sleep also affects gene expression, hormone regulation and brain detoxification, just to mention a few, which further strengthens its importance for general health and longevity, so…
Eat healthy, Be healthy, Live lively, Get good Sleep
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