They noted that people with lower incomes tend to have more sleep-related disorders due to off-hour shifts, lack of healthcare services, and daily stress.
They said having regular checkups with a doctor and developing healthy sleep habits can reduce these risks.
Not getting enough sleep is one risk factor for cardiovascular disease.
And for a variety of reasons, people with lower socioeconomic status tend to sleep less.
That may be part of the reason people with lower incomes have more heart-health issues, according to a study published in the journal Cardiovascular Research.
Researchers noted that people who work off-hour shifts, live in deprived neighborhoods, or experienced adversity in childhood have a higher prevalence of sleep-related disorders.
They suggested that social inequalities may play a role in cardiovascular disease, which includes heart disease and stroke.
About the study
Data for the study came from 111,205 participants in four European countries.
Economic status was classified as low, middle, or high depending on the participant’s occupation as well as their father’s occupation. Level of education was also considered.
Sleep duration was self-reported. Normal sleep was categorized as between 6 and 8.5 hours. Less than that was categorized as short sleep and more than that as long sleep.
History of heart disease and stroke was included.
The researchers found that less sleep accounted for 13 percent of the link between occupation and heart disease in men.
This link wasn’t as strong in women. The researchers theorize that women may have more responsibilities aside from occupation that affect sleep and overall health.
What the study tells us
Sanjiv Patel, MD, is a cardiologist at MemorialCare Heart & Vascular Institute at Orange Coast Medical Center in Fountain Valley, California.
“It was population-based data collection with a lot of patients and good followup,” he told Healthline. “The study basically concludes that lower sleep hours have an adverse impact on a person’s health, which is appropriately stated. Looking at the increased risk of heart disease, the likely association makes sense.”
“But that doesn’t say that less sleep leads to elevated risk of heart disease all by itself,” Dr. Patel added. “The more important issue is that sleep helps drive health and well-being. Why are these people not sleeping well?”
Although it was a European study, Patel says certain human patterns can be generalized.If you have more stress, the less you sleep, and the worse health outcome in general — not just heart disease,” he said.
Victoria Shin, MD, is a cardiologist at Torrance Memorial Medical Center in California. She told Healthline this was a robust cross-sectional study, but she wonders whether the researchers accounted for people with sleep apnea.
“Sleep apnea is a particular sleep disorder in which patients think they are getting adequate sleep, but it is fragmented and disturbed due to breathing issues,” she explained. “Those patients have a higher incidence of high blood pressure and arrhythmias, which can tie into cardiovascular events.”
“Given the cultural and racial heterogeneity of the United States versus Europe, I’m not sure it can be extrapolated directly,” she added. “But it points out an important modifiable risk factor that should be assessed in the United States as well.”
Risk factors and signs
Dr. Shin explained that the heart is a supply and demand system.
“If there’s a problem with the supply (the heart) and you increase the demand (activity), you may have symptoms such as chest discomfort or shortness of breath. Sometimes it’s as subtle as decrease in exercise tolerance or an inability to do activities you did before due to fatigue or lack of energy,” she said.
Some risk factors have to do with what’s lacking, she added.
“Lack of access to healthcare. Lack of access to nutritional foods and more fast food restaurants located in lower income areas. Lack of access to exercise, such as gyms. And lack of time to exercise given that many people have two or three jobs and work shifts while still taking care of their families,” said Shin.
Patel said diabetes, obesity, smoking, and family history of heart disease are also risk factors.
“All of these things are prevalent in lower socioeconomic groups by default. Their lives may be more stressful day in and day out. The consequence of not sleeping well is more stress. Spending more of the day awake causes stress hormones to trigger other diseases. It lowers immunity and raises the risk of infection and inflammation,” he added.
Unfortunately, said Patel, heart disease and stroke don’t always produce symptoms until it’s late in the process.
“You can get up to 50 to 70 percent narrowing of arteries before getting symptoms like difficulty breathing and chest pressure. It takes time for that to occur. Same thing with stroke signs. Sudden onset loss of speech, blurry vision, or numbness in one part of the body can come and go or be permanent,” said Patel.
He cautions that ignoring symptoms can lead to a worse outcome.