Young athletes who suffer from sleep disruptions may be at a higher risk for sudden cardiac death.
A Japanese research team has found that young athletes are both more likely to suffer from sleep disordered breathing (SDB) than an average, middle-aged man and are more likely to have lower oxygen levels in their blood with higher pulse rates at night, suggesting that they may be at risk for heart abnormalities.
“We wanted to investigate the prevalence of sleep disordered breathing in collision sport athletes, such as rugby or American-style football players, because we know that they usually have a higher BMI [body mass index] and larger neck circumference than athletes from other sports,” Yoshitaka Iso, a cardiologist and associate professor at Showa University Research Institute for Sport and Exercise Sciences, said in a statement. “We tend to assume that young, competitive athletes will not experience conditions like SDB, which are more common in people with a higher BMI and inactive lifestyles, but more research is needed to determine what may be contributing to sudden cardiac death in athletes, and SDB is a good candidate for this as it can affect the heart’s normal functions.”
Some of the symptoms of SDB include abnormal respiratory patterns or pauses in breathing during sleep, which range from snoring to sleep apnea when the airways close completely or partially over the course of sleeping. Many individuals over 40 with a high BMI and a large neck circumference have some of the common factors associated with SDB. When untreated, patients face an increased risk of a number of chronic diseases, including cardiovascular disease, heart failure and type 2 diabetes.
The researchers examined 42 male rugby players between 18 and 19 years old with a device that monitors overnight changes of breathing rhythm, heartbeat, heart rate, blood oxygen levels, the number of times they woke up, and how long they were awake. They found that 43 percent of the athletes experienced five or more pauses in breathing that lasted at least 10 seconds over a total sleeping time of more than three hours, meeting the criteria for SDB.
The data also showed that the volunteers with SDB had higher than average heart rates with lower levels of oxygen in their blood, with more periods of time when their blood oxygen levels were unusually low than the athletes who did not suffer from SDB.
The research team then assessed the performance of each patient’s heart and lungs at both rest and during activity to see if there were cardiovascular abnormalities among the athletes with and without SDB. They found that the resting heart rate among SDB athletes was higher and they experienced more incidences of extra or disruptive heartbeats.
“Sleep disordered breathing was observed in 43 percent of the young athletes we assessed,” Iso said. “This is a higher rate than we expected, and is higher still than the levels of SDB reported among middle-aged men from the general population of the US and Europe. Our data also showed that several potential warning signs, such as effects on the athletes’ breathing and heart rates, occurred frequently among the athletes with SDB.
“Although none of the athletes in this study were found to have serious conditions yet, likely due to their young ages, we do not know how their conditions may worsen in the future due to associated cardiovascular consequences,” he added. “Based on the link between SDB and abnormal heart functions that we observed in this group, we speculate that SDB could be a possible factor in the unexplained deaths of some young collision sport athletes, as it appears to be very prevalent but currently is not regularly screened for.”
While the researchers said it was too early to definitively link SDB and sudden cardiac death for athletes, the study results highlight the need for an additional large study to confirm the results and determine the underlying mechanisms that lead to the disease. The initial study was also conducted during only one night of sleep and the researchers plan to assess performance during a multiple night study.
There have been several notable examples of athletes collapsing and ultimately dying due to sudden cardiac arrest, including Boston Celtics forward Reggie Lewis in 1993, Chicago Bears defensive end Gaines Adams in 2010 and Atlanta Hawks center Jason Collier in 2005. Perhaps the most famous example of an athlete succumbing to sudden cardiac death occurred in 1990 when 23-year old Loyola Marymount University forward Hank Gathers collapsed and died shortly after an alley-oop in a basketball game.
The study was published in ERJ Open Research.