Sleep apnea & your heart
Obstructive sleep apnea (OSA) affects approximately 1 in 5 people globally (1) and is a leading cause of recurring interruptions in nighttime breathing. These interruptions occur when airflow is reduced or stopped altogether due to the relaxation of throat muscles during sleep. When the soft throat tissue collapses, and the upper airway is restricted, it results in partial reductions (hypopneas) or complete pauses (apneas) in breathing.
OSA is classified by severity based on a measurement and rating system called the apnea-hypopnea index (AHI), which measures the average number of apnea and hypopnea episodes per hour:
- Severe OSA = Apnea-hypopnea index (AHI) is > 30 (i.e., more than 30 episodes per hour)
- Moderate OSA = AHI is between 15 - 30
- Mild OSA = AHI is between 5 - 15
Symptoms of OSA include:
- Snoring, especially snoring that’s interrupted with periods of quiet (i.e., an apnea episode)
- Excessive daytime sleepiness/grogginess despite a full night’s sleep
- Breathing interruptions or awakenings due to gasping/choking, witnessed by family/friends
- Dry mouth on waking
- Morning headaches
An official diagnosis of OSA requires a sleep study, typically in a sleep clinic, but it can also be done at home. FYI, you can take a preliminary self-assessment using The Epworth Sleepiness Scale. It’s just a simple questionnaire, but it might give you a sense of your risk profile.
It’s important to know sleep apnea is not just a nuisance or fodder for family entertainment (did you hear grandad snoring last night!); it’s a serious condition with potentially life-threatening consequences. The repeated drops in blood oxygen levels that occur with sleep apnea stress the cardiovascular system.
So, what is the link between OSA and Cardiometabolic health?
This stress — of the drops in blood oxygen levels — can lead to a range of heart issues, including:
- Hypertension (High Blood Pressure): The sporadic drops in blood oxygen levels during sleep can lead to elevated blood pressure, a major risk factor for heart disease and stroke.
- Coronary Artery Disease (CAD): Sleep apnea has been linked to the development and progression of CAD, a condition in which the blood vessels supplying the heart become narrowed or blocked.
- “Recurrent periods of hypoxemia followed by reoxygenation promote reactive oxygen species (ROS) overproduction and increase inflammatory response”(2).
- Heart Failure: The strain on the heart from untreated sleep apnea can contribute to heart failure, where the heart is unable to pump enough blood to meet the body's needs.
- “Hypoxic and ventilatory burden predicted CVD morbidity and mortality in two population-based studies.” (3)
- Arrhythmias: Sleep apnea increases the risk of abnormal heart rhythms, such as atrial fibrillation, which can further raise the risk of stroke and heart failure.
Furthermore, there’s a bidirectional relationship between your overall health status and OSA
OSA is considered an independent risk factor for other cardiometabolic health issues, including pre-diabetes, diabetes, elevated cholesterol, and increased weight around the midsection. These conditions (aka comorbidities) are more recently being considered risk factors for the development of OSA (4).
Standard risk factors for OSA include (5):
- Large/thick neck ( > 16” for women, > 17” for men)
- Narrowed airway (FYI, tonsils/adenoids can enlarge and block the airways)
- Age (OSA occurs significantly more often in older adults)
- Thyroid disorder or other endocrine condition
- Alcohol, sedatives, or tranquilizers (all relax muscles in the throat, which can worsen OSA)*
- Smoking*
- Excess weight*
- Chronic nasal congestion*
* Readily influenced by your everyday food and lifestyle choices.
My recommendations to reduce your risk of OSA are as follows:
- Prioritize having a healthy body composition with regular exercise & healthy food choices
- In a study published in JAMA Network Open, researchers in Spain recruited 89 overweight men with moderate to severe OSA; they split them into 2 groups - both groups used a CPAP (continuous positive airway pressure) device (the standard treatment for OSA), but only one group was counseled to adopt healthier food and lifestyle habits.
After just 8 weeks, those in the healthy habits group experienced a 51% reduction in apnea episodes. About 15% achieved complete remission, and 45% no longer needed their CPAP machines! (6) - To date, the primary approach to OSA has focused on weight reduction. A 13% weight reduction has been shown to decrease upper airway collapsibility by modifying its anatomy and function. Even 10% weight loss can reduce AHI from 55 to 29 per hour (7).
- Reduce alcohol
- One meta-analysis found high levels of alcohol increased the risk of OSA by 25% (8)
- Reduce inflammation
- Regulate your blood sugar
- Prioritize phytonutrient-rich foods
- Optimize your gastrointestinal function
If you, or someone you love, snores loudly and feel(s) consistently tired even after a full night’s sleep, don't hesitate to seek medical advice. Addressing sleep apnea can improve your quality of sleep and overall well-being and significantly reduce the risk of developing heart disease and its associated complications.
As always, please don’t hesitate to reach out with questions/comments.
References:
- Lechat, B., et al (2022). Multinight prevalence, variability, and diagnostic misclassification of obstructive sleep apnea. American Journal of Respiratory & Critical Care Medicine, 205(5), 563-569.
- Mochol, J., et al (2021). Cardiovascular disorders triggered by obstructive sleep apnea - A focus on endothelial and blood components. International Journal of Molecular Science, 12;22 (1), 5139
- Labarca, G., et al (2023). Sleep apnea physiological burdens and cardiovascular morbidity and mortality. American Journal of Respiratory & Critical Care Medicine, 208 (7), 802-813, doi: 10.1164/rccm.202209-1808OC
- Gleeson, M., McNicholas, W. T. (2022). Bidirectional relationships of comorbidity with obstructive sleep apnea. European Respiratory Review, 31: 210256
- Mayo Clinic staff https://www.mayoclinic.org/diseases-conditions/sleep-apnea/symptoms-causes/syc-20377631
- Carneiro-Barrera, A., et al, (2022). Effect of an Interdisciplinary Weight Loss and Lifestyle Intervention on Obstructive Sleep Apnea Severity. The INTERAPNEA Randomized Clinical Trial. JAMA Network Open, 5(4)
- Shah, N., Roux, F. (2009). The relationship of obesity and obstructive sleep apnea. Clinics in Chest Medicine, 30(3), 455-465
- Simou, E. , Britton, J. & Leonardi-Bee, J. (2018). Alcohol and the risk of sleep apnoea: a systematic review and meta-analysis. Sleep Medicine, 42: 38-46