Sleep is a vital component of overall health. It affects a wide range of physiological and psychological functions. Sleep irregularities such as insomnia, disrupted circadian balance, sleep apnea, and variations in sleep duration pose increasing risks to health.
Man Sleeping
Cardiovascular diseases, which encompasses hypertension, heart attacks, and stroke, remain the highest cause of death worldwide. Emerging research suggests that sleep irregularities may play a role in the development and progression of cardiovascular diseases (CVD).
Kannan R. et al. (2021) assert that healthy sleep is vital for normal cognitive function, mood, mental health, cardiovascular (CVD), cerebrovascular and metabolic well-being. The same study shows that prolonged sleep deprivation, disrupted circadian rhythms, and unmanaged sleep disorders can be detrimental to mood, mental and physical health, and the general safety of the public.
Growing evidence shows a connection between disruption of the circadian rhythm and cardiovascular diseases. Despite this, it is still unsure whether this link can be modified by sleep duration or genetic predisposition to CVD.
How Sleep Irregularities Can Cause CVD
Several physiological mechanisms mediate the connection between irregular sleeping and CVD.
Blood Pressure
One such mechanism is the effect of sleep on blood pressure, which dips naturally during non-rapid eye movement (NREM) sleep. This effect is known as Nocturnal dipping, and it helps reduce the strain on the cardiovascular system. In sleep disorders such as insomnia, disruption of this pattern causes a nocturnal increase in blood pressure. Chronic elevation of blood pressure increases the risk of developing hypertension, which can predispose one to CVD.
Metabolic disruptions
Insufficient sleep has been associated with alteration of glucose metabolism, reduced insulin sensitivity, and increased appetite- all of which contribute to the development of type 2 diabetes, obesity, and dyslipidemia, which further increases the risk for developing hypertension, atherosclerosis, and other CVD.
Inflammation
Systemic inflammation has been linked to sleep irregularities and is a critical factor in the development and progression of atherosclerosis. Disrupted sleep patterns lead to the elevation of pro-inflammatory cytokines like C-reactive protein, which can lead to chronic inflammation. This inflammation can further lead to endothelial dysfunction, promoting the development of atherosclerotic plaques. This inflammatory response can worsen already existing cardiovascular conditions.
Stress response
The hypothalamic-pituitary-adrenal (HPA) axis is closely associated with sleep regulation. Poor sleep quality can disrupt the regulation of the HPA axis, leading to the elevation of stress hormones such as cortisol and adrenaline. These hormones elevate blood glucose levels, heart rate, and blood pressure, contributing to a higher risk of CVD.
Too much sleep might not necessarily be better.
Studies show that participants with higher sleep duration irregularities tended to be younger, female, non-white, of lower socioeconomic status, employed in shift work, and more likely to have an increased Body Mass Index.
There is also a similarity in the observed increased risk for CVD associated with irregularities in sleep for Myocardial infarction (MI) and stroke.
Quite interestingly, even though shorter sleepers tended to show more sleep duration irregularity, the longer sleepers appeared more prone to the adverse effects of the risk of CVD by sleep irregularities.
Conclusion
Yes, inadequate sleep duration can increase the risk of developing or exacerbating cardiovascular diseases. On the other hand, longer sleep duration poses a greater risk of developing CVDs. Therefore, like with most bodily processes one has to strike a balance between too little sleep and too much of it to optimize cardiac function.
References
Ramar K, Malhotra RK, Carden KA, et al. Sleep is essential to health: an American Academy of Sleep Medicine position statement. J Clin Sleep Med. 2021;17(10):2115–2119. https://doi.org/10.5664/jcsm.9476
Huang T., Kianersi S., Wang H., Potts K.S., Noordam R., Sofer T., Rutter M.K., Redline S.(2024). Sleep duration irregularity and risk for incident cardiovascular disease in the UK Biobank. MedRxiv doi: https://doi.org/10.1101/2024.07.26.24311090
FEEDBACK: