It has become common knowledge that getting too little sleep is unhealthy. Lack of sleep ups the risk for heart disease, high blood pressure, stroke and diabetes, according to WebMD. It can also impair cognitive ability, reduce sex drive and contribute to depression.
Now comes word from a recent study conducted at the University of Sydney in Australia that getting too much sleep – more than nine hours a night – is even worse for you than getting too little sleep.
Dr. John Suen, MD, is the medical director of Sleep Disorders Center Florida, an accredited medical treatment center for sleep-related issues located in Vero Beach. Dr. Suen is familiar with the University of Sydney study, and says that while the research is preliminary, it raises good questions that are worthy of additional discussion and research.
“One thing the study doesn’t explain is why there is an increased risk of death for those who are long-sleepers,” Dr. Suen says. “No cause and effect was determined, and any underlying medical conditions, such as sleep apnea, were not taken into consideration.”
The Australian study found that, for the first time in human history, non-communicable diseases (NCDs) are killing more people than infectious diseases. The most common NCDs are: cardiovascular diseases, cancers, diabetes, and chronic respiratory diseases.
The traditional risk factors for NCDs can be attributed to four modifiable lifestyle choices: smoking, harmful use of alcohol, physical inactivity, and having an unhealthy diet. Now the team at the University of Sydney has identified two additional lifestyle risk factors: unhealthy sleep durations (less than seven or more than nine hours of sleep per day) and prolonged sitting (sitting for more than seven hours a day).
The University of Sydney researchers received self-reported lifestyle risk factors from over 230,000 middle-aged and older study participants during the three-year period from 2006-2009; the researchers then compared that data to reported deaths as of June 2014. The results showed that one of the riskiest of the risk factors was a combination of physical inactivity, prolonged sitting, and long sleep duration. (According to the study, it’s more dangerous to our health to sleep too much than too little.) The risk of this particular combination was akin to that of lifestyle factors involving smoking and high alcohol use.
You can still be at risk from prolonged sitting even if you are physically active, defined in the study as undertaking more than two and a half hours of moderate-to-vigorous physical activity every week. So we can take a brisk two-mile walk three times a week, but still have a sedentary, and therefore unhealthy, lifestyle. Vero’s Dr. Suen understands that people often do need to sit for long stretches; his guidance is to get up and walk around every hour or so, if only for a few minutes.
The study authors say that the six modifiable lifestyle risk factors mentioned above tend to be associated with multiple diseases and conditions.
Dr. Suen says that there is no specific number of hours of nightly sleep that works for everyone. “What’s right is whatever makes you feel rested, which is typically seven to eight hours, but it varies by individual,” he says. However, he does says that it’s very unusual for someone to need less than four hours of sleep. “People will say they can function fine consistently sleeping only four hours, but they’re fooling themselves. They often compensate with a lot of caffeine, and by pushing themselves. It’s not a healthy way to live.”
Dr. Suen is board-certified in sleep medicine, pulmonary disease, internal medicine and critical care medicine. Sleep Disorders Center Florida is located at 3735 11th Circle #103 in Vero Beach; the phone number is 772-563-2910.
