Whether or not you are living with CVD, let’s level set about cardiovascular health and the relationship with sleep and circadian health by acknowledging that this relationship is so important that, in 2022, the American Heart Association (AHA) added sleep duration as its eighth pillar of health, now known as Life’s Essential 8™.² Then again, in 2025, the AHA doubled down on this commitment with a published scientific statement emphasizing the multidimensional aspect of sleep and its relationship to cardiometabolic health (CMH).³ Their updated position emphasized the dimensions of sleep to include not only duration, but also regularity, quality, timing, efficiency, architecture, and continuity (lack of disruption), as well as a measure of alertness when awake, which was further underscored by the evidence regarding the increased risk for CMH due to suboptimal sleep and circadian health. 

Sleep and Circadian Disorders and CVD

When examining the relationship of heart health with sleep and circadian patterns, you will find there is more to it than just good habits as a preventative heart health strategy. In fact, when researchers examined the effects of sleep apnea in an animal model, they discovered that the animals developed high blood pressure and stiff arteries or blood vessels that don’t relax properly.⁴  

But, does this translate to humans? Yes, it appears so! A comprehensive review of published research that had evaluated the association between sleep disorders in adults and CVD found that, yes, this in fact is a concern for humans, too. However, it didn’t stop at obstructive sleep apnea (OSA), but also included multiple conditions like central sleep apnea (CSA), narcolepsy, and insomnia as being associated with an increased risk of developing CVD.⁵ 

How do sleep and circadian problems make us more likely to experience CVD?  Although there are different mechanisms related to various sleep disorders like chronic insomnia, periodic limb movement disorder, and CSA or OSA, all of these can contribute to our autonomic nervous system becoming a bit dysregulated. This represents one of the common consequences of sleep and circadian problems. Our bodies remain in a heightened sympathetic (fight-or-flight) state,  rather than the parasympathetic (rest-and-restore) state that is expected to occur with healthy restorative sleep. This heightened stress can cause damage to the lining of blood vessels, increase inflammation, and cause other health problems. Over time, sleep and circadian problems can lead to increased rates of CVD, including high blood pressure, heart failure, blocked arteries in the heart and periphery, stroke, irregular or abnormal heartbeat, and other problems. When sleep is continually interrupted, we can have excessive daytime sleepiness, fatigue, and mood changes, not to mention difficulty thinking or remembering things. Finally, sleep and circadian problems can even increase the risk of dying.⁴

Let’s take a step further. You may be surprised to know that there is an expected timing of heart attacks (myocardial infarction, MI), sudden cardiac death, chest pain (angina), and abnormal heart rhythms that originate in the lower heart chamber (ventricular arrhythmia)  to occur. That’s right. When studied, it has been shown that these conditions are more likely to occur in the morning hours. Coincidence? Not at all! The pattern of these events overlaps with the patterns of physiologic processes that would promote higher blood pressures, increased stickiness of certain blood cells, and even increased resistance in blood vessels (slower flow).⁶ In other words, it’s a recipe for risk. 

Why? It’s not a coincidence. It’s circadian! Perhaps, not something that should prompt us to be fearful, but more of an opportunity for us to be proactive in our behaviors and also think about the role of chronotherapy, or timing medications to our circadian patterns to optimize efficacy. 

Ever work the graveyard shift or have a rotating work schedule that wreaked havoc on your sleep schedule? Then you have experienced something called circadian misalignment. Circadian misalignment, or circadian rhythm disorders, occur when a person’s body’s natural clock is not in sync with their daily schedule, such as working the night shift or being exposed to artificial light at night. This misalignment is not just a social inconvenience; it is a real health risk, increasing the odds of experiencing high blood pressure, inflammation, CVD, and more.

Unfortunately, when it comes to work or school, we sometimes justify the sleep sacrifice as “necessary” or temporary and just something to power through. But would we think that way if we “knew” it was harming us?

To better understand the consequences of circadian misalignment, researchers⁷ created simulated shift-work conditions by having 14 healthy young adult volunteers live in their laboratory for two 8-day periods. The participants spent the first 8 days having their circadian rhythms rigidly entrained to a normal day-night cycle that included darkness from 11 p.m. to 7 a.m. During the second 8 days, the light and dark cycles were reversed, with the dark cycle moving to 11 a.m. to 7 p.m. The researchers tested the participants’ amount of sleep, 24-hour blood pressure, and blood markers of inflammation, among other parameters. 

What did they find? Even this short-term circadian misalignment led to increased blood pressure, as well as a sleep-related finding called a nondipping status, which commonly occurs as a predictor of the development of hypertension. Normally, during sleep, our bodies experience a “dip” in blood pressure, reflecting that parasympathetic or rest-and-restore state. As if that were not enough, the researchers⁷ also identified increased inflammatory markers, another risk factor for developing CVD. The researchers concluded that their study results provide “evidence for circadian misalignment as an underlying mechanism to explain why shift work is a risk factor for hypertension and CVD.”⁷

If you are living with CVD, you may be prescribed medications that can influence your sleep-wake cycles and even contribute to the experience of sleepiness. It is not uncommon for a person living with CVD or CV risk factors like diabetes, overweight, obesity, or hypertension to describe feelings of being “tired,” “run down,” “fatigued,” or “sleepy.” First, it is important to specifically call out that these are not the same thing. 

We know it sounds nitpicky, but why waste the time distinguishing these terms? Communication matters! If you are telling your story, but the description is inaccurate, then your diagnosis and treatment may also end up being inaccurate. 

Some medications that may be used to treat heart and blood vessel conditions (in cardiology) can affect your sleep and also contribute to feeling less than optimal during the day, including reports of sleepiness and fatigue.⁸ The more likely culprits include beta blockers (e.g., propranolol, metoprolol), calcium-channel blockers (e.g.,  verapamil, amlodipine), and centrally acting alpha-2 adrenergic agonists (e.g., clonidine). For instance, beta blockers can cause insomnia, nightmares, visual hallucinations, and daytime sleepiness. On the other hand, medications like angiotensin-converting enzyme inhibitors (e.g., benazepril, captopril,  or enalapril), angiotensin II receptor blockers or inhibitors (e.g., losartan, valsartan), and vasodilators (hydralazine, nitroglycerin, minoxidil) may be less problematic. 

If it feels like you’re trying to figure out which is the chicken or the egg, keep track of your concerns, and see if there is a relationship to the timing of medication use or whether it is more influenced by your CVD or something else. It is important to distinguish for yourself because, unfortunately, medical guidelines still lack the comprehensive sleep and circadian approach needed to address any person anywhere. 

What do we mean? Well, although we are glad to see that the AHA issued a scientific statement  in 2021 regarding screening for OSA in people who have a number of heart conditions⁹ and further evaluations for others^,10 more than OSA can exist, with or without the presence of OSA, and cause problems during the day and night. In 2023, the AHA provided guidelines for the treatment of atrial fibrillation (when the upper two chambers of the heart–the atria–beat irregularly and quickly) saying that “it may be reasonable to screen for [OSA], given its high prevalence in patients with AF, although the role of treatment of sleep-disordered breathing to maintain sinus rhythm is uncertain.”¹¹ It is noteworthy, that these guidelines came 3 years after the American College of Cardiology had already made this strong suggestion, but even went further stating perhaps a sleep study, not even just OSA surveys or screening, when considering those who will be undergoing an ablation, or procedure that attempts to isolate and stop the abnormal rhythm.¹² Current evidence demonstrates that, although adherence to continuous positive airway pressure (CPAP) in the first year after catheter ablation did not impact AF recurrence rates in patients with severe OSA, there were substantial differences beyond 1 year, with significantly lower recurrence in patients with long-term CPAP treatment than in those without (7.6% versus 21.6%).¹³ 

2021 AHA recommendations for screening for OSA⁹

• People with high blood pressure that is not well-controlled on medication (systemic hypertension)
• People with high pressure in the blood vessels of the lungs (pulmonary hypertension)
• People with blood pressure that does not decrease during sleep (nondipping nocturnal blood pressure profile)
• People with repeated slower heart rates due to abnormal heart rhythm (repetitive bradyarrhythmias)
• People with irregular and rapid beating of the upper two chambers of the heart (atrial fibrillation) that starts again after treatment with shocking the heart or surgery to block the abnormal signals that cause the atrial fibrillation (atrial fibrillation after cardioversion or ablation)

People who have signs and symptoms of OSA and any of the following conditions should be considered for further evaluation for the presence of sleep-disordered breathing.

• People with heart failure (New York Heart Association Class II-IV)
• People with tachy-brady and sick sinus syndrome
• People with ventricular tachycardia 
• People who survive sudden cardiac death
• People who have had a stroke
• People who have had a heart attack (myocardial infarction) or atrial fibrillation during sleep
• People who have an implantable cardioverter-defibrillator and receive a shock during sleep

Let’s take a moment to appreciate the guidance that if you have one of the above conditions and have not been screened for OSA, you may want to reach out to your healthcare provider to ask about screening. We would offer to take it one step further. Don’t forget to share any sleep- or wake-related symptoms that may represent a sleep or circadian disorder that may need to be addressed. Even though the AHA guidelines are specific to OSA, we hope to see future updates to reflect a more comprehensive sleep and circadian approach.

References

1. World Health Organization. Cardiovascular diseases (CVDs). https://www.who.int/news-room/fact-sheets/detail/cardiovascular-diseases-(cvds). Published 2021. Accessed May 19, 2025.
2. Lloyd-Jones DM, Allen NB, Anderson CAM, et al. Life’s Essential 8: updating and enhancing the American Heart Association’s construct of cardiovascular health: a presidential advisory from the American Heart Association. Circulation. 2022;146(5):e18-e43.
3. St-Onge M-P, Aggarwal B, Fernandez-Mendoza J, al. e. Multidimensional sleep health: definitions and implications for cardiometabolic health: a scientific statement from the American Heart Association. Circulation. 2025;18(5):e000139.
4. Badran M, Puech C, Gozal D. The cardiovascular consequences of chronic sleep fragmentation: evidence from experimental models of obstructive sleep apnea. Sleep Med. 2025.
5. Ravichandran R, Gupta L, Singh M, Nag A, Thomas J, Panjiyar BK. The interplay between sleep disorders and cardiovascular diseases: a systematic review. Cureus. 2023;15(9):e45898.
6. Hausmann D, Nikutta P, Trappe H-J, Daniel WG, Wenziaff P, Lichtien PR. Circadian distribution of the characteristics of ischemic episodes in patients with stable coronary artery disease. Am J Cardiol. 1990;66(7):668-672.
7. Morris CJ, Purvis TE, Hu K, Scheer FA. Circadian misalignment increases cardiovascular disease risk factors in humans. Proc Natl Acad Sci U S A. 2016;113(10):E1402-1411.
8. Carnovale C, Perrotta C, Baldelli S, et al. Antihypertensive drugs and brain function: mechanisms underlying therapeutically beneficial and harmful neuropsychiatric effects. Cardiovasc Res. 2023;119(3):647-667.
9. Yeghiazarians Y, Jneid H, Tietjens JR, et al. Obstructive sleep apnea and cardiovascular disease: a scientific statement from the American Heart Association. Circulation. 2021;144(3):e56-e67.
10. Mansukhani MP, Somers VK. Whom to screen and how to screen for obstructive sleep apnea in the cardiology clinic. Circulation. 2023;147(8):621-623.
11. Joglar JA, Chung MK, Armbruster AL, et al. 2023 ACC/AHA/ACCP/HRS Guideline for the diagnosis and management of atrial fibrillation: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation. 2024;149(1):e1-e156.
12. Shapira-Daniels A, Mohanty S, Contreras-Valdes FM, et al. Prevalence of undiagnosed sleep apnea in patients with atrial fibrillation and its impact on therapy. JACC Clin Electrophysiol. 2020;6(12):1499-1506. https://www.acc.org/latest-in-cardiology/journal-scans/2020/11/25/15/46/prevalence-of-undiagnosed-sle
13. Tanaka N, Okada M, Tanaka K, et al. Impact of long-term CPAP adherence on recurrence after atrial fibrillation ablation in patients with severe sleep apnea. J Am Heart Assoc. 2025;14(10):e038742