Researchers at Tulane University in New Orleans studied 385,292 participants who were genetically susceptible to cardiovascular problems at various levels: high, intermediate, and low. Participants were scored between 1 to 5 based on their sleep patterns, with 1 being the worst quality sleep and 5 being the healthiest. Someone with a score of 5 meant that they got 8 hours of quality sleep every night, without insomnia.
The study found that quality sleepers were at less risk of developing cardiovascular problems and that those with unhealthy sleep routines were at higher risks.
Those with a score of 5 had a 34 percent less risk of both heart disease and stroke, compared to those who scored between 0 and 1.
Meanwhile, participants with a low sleep score and high genetic risk were more than 2.5 times more likely to develop heart disease. They were also 1.5 times more likely to suffer a stroke.
“Among people with a healthy sleep score of 5, there were nearly seven fewer cases of cardiovascular disease per 1000 people per year compared to those with a sleep score of less than 5,” said research leader and professor Lu Qi.
The study also found that people who get eight hours of sleep is related to a reduced risk of heart disease and stroke, despite their high genetic susceptibility. The genetical variation researchers analyzed in the participants are called single nucleotide polymorphisms or SNPs.
During the study, which was conducted over a period of eight and a half years, there were 7,280 cases of cardiovascular disease, 4,667 cases of heart disease, and 2,650 strokes among participants. Those with the greatest protection had the lowest genetic risk and best sleeping patterns.
“We found that a high genetic risk could be partly offset by a healthy sleep pattern,” said Qi. “We wanted to test whether the relation between sleep scores and cardiovascular outcomes was different according to the genetic risk.”
“We also wanted to estimate the proportion of cardiovascular problems that would not have occurred if all participants had a healthy sleep pattern, if we assume there is a causal relationship.”
“In addition, we found that people with low genetic risk could lose this inherent protection if they had a poor sleep pattern.”