How Under- and Oversleeping Can Adversely Affect Shipping Crewmembers
Most people know to sleep between six and eight hours a night, though where in this range you fall depends on both age and lifestyle. Elderly and active individuals, for instance, may land on the longer-end of this spectrum. Moreover, there are periods when the body may require more sleep, such as during an illness or after a physical trauma. Jet lag, too, is curable through extended rest. Generally, however, we should spend only 33% of our lives sleeping; anything greater or lesser can lead to health complications. Sleep deprivation can cause many problems, including high blood pressure and diabetes—two factors that reduce blood flow to the brain. In effect, those who sleep too little suffer from cognitive deficiencies, especially in regards to memory and decision-making. Yet sleeping too much induces similar effects, compounded with a phenomenon known as “sleep drunkenness.” This explains why you may sometimes feel groggy or dizzy after long bouts of sleep. Note that sleep drunkenness is harmless: it only grows into a concern if it occurs daily. But why do people experience negative effects from oversleeping? This question has fueled many studies, though a concrete answer has yet to emerge. One theory posits oversleep results in poor sleep quality, which can sometimes be just as bad as sleeping too little. This makes sense because the brain cleanses itself during sleep, eliminating toxins and processing data; therefore, these natural processes are greatly disturbed if the quality of sleep falls below what it should. Surprisingly, studies even link “disturbed sleep” with a smaller brain!
Consequences of Oversleeping for Shipping Crewmembers
A study featured in the Journal of the American Geriatrics Society examines the sleep habits of middle-aged men and women, discovering those who under- and oversleep are on average mentally two years old. This supports a report in the Harvard-based Nurses’ Health Study that argues adequate sleep helps to maintain memory function with age. In addition, poor sleep quality can impact a person physically. For instance, Plos One cites a study that correlates oversleep with depression. Similarly, a study from Quebec reveals those who sleep in excess are twice as likely to develop type-2 diabetes. These results coincide with an earlier investigation that assessed weight gain in French-Canadians over a six-year period, concluding under- and over-sleepers gained the most. Maintaining a poor sleep schedule can also impact your heart. Researchers at the 2012 American College of Cardiology suggested oversleep heightens the risk of angina by two and the risk of coronary artery disease by 1.1. Likewise, oversleep and under-sleep both increase the risk of early fatality, though not from any cause specifically. In light of such research, seafarers should aim to sleep only six to eight hours a night, including weekends, days off and vacation time!