Does sleep deprivation lead to risky decisions?
Whether due to stress, jet lag, a busy schedule or medical conditions, sleep deprivation has a distinct and decidedly negative effect on our abilities to function well physically and mentally.
Though we all have varying needs for sleep (one person's five-hour beauty sleep may leave another person drowsy), you should generally get between seven and nine hours of sleep in a single day. You create a sleep debt when you fall an hour or two short of your needed sleep day after day. Sleep deprivation over the course of a week can lead to cognitive difficulties that are similar to those experienced by stroke patients [source: Stevens]. The result can be dangerous for those working long hours. Studies show medical residents experience more accidents after putting in long shifts [source: Durmer].
Drivers who are sleep deprived are as bad as -- and sometimes worse than -- intoxicated drivers in studies that have tested both groups using driving simulators. According to the National Highway Traffic Safety Administration, there are around 100,000 traffic accidents a year due to sleep deprivation and 1,550 fatalities [source: Breus].
Sleep deprivation affects your body and mind in myriad ways. As a sleep debt builds, your ability to concentrate decreases. Thinking becomes labored, and vision becomes blurry. You may experience headaches or feel especially agitated or moody. You start to forget things.
The immune system takes a hit as well. When sleep deprived, you have fewer white blood cells, and those you do have aren't very effective in destroying unwanted antigens in the body. Your body temperature drops, and your heartbeat can become erratic. The greater the sleep debt, the more difficult it is to process visual information.
You're feeling weak, distracted, foggy and upset. You have a headache, and you can't see straight. Think these are bad circumstances for making decisions? Research shows that when you're sleep deprived, there's more activity in the parts of your brain that analyze positive outcomes and less activity in parts responsible for weighing negative outcomes.
Whether you're caring for patients in a hospital, pulling a double shift at the factory, piloting a passenger plane or driving a truck, you're more likely to make an error [source: Durmer].
In what other ways does sleep deprivation affect decision making? Odds are, you're not ready for a weekend in Vegas.
Danger Behind the Roulette Wheel
Sleep deprivation affects the brain in ways that can be detected through imaging. Lack of sleep alters the brain's metabolism; it produces less growth hormone. Some parts of the brain become much less active as your sleep debt grows, while others become busier as they attempt to compensate.
For instance, the temporal lobe -- which assists in language processing -- becomes less active the longer you stay awake, while a related area -- the parietal region -- partially makes up for the slack by becoming more active [source: UC San Diego Health System].
One study showed sleep-deprived subjects exhibited diminished activity in the regions of the brain that handle mathematics. No other region stepped up to help, so participants did much worse when doing mathematics on little sleep.
Without sleep, you also have slower reaction times and more difficulty with fine motor skills, which are controlled by the brain's motor cortex in the rear of the frontal lobe. And you become more impulsive and less inhibited [source: Anderson]. Combined with all the other detrimental effects of sleep deprivation, diminished ability to make good decisions can lead to lots of trouble.
Nobody knows this better than casinos, which benefit most when you're not thinking clearly. Casinos use several tricks to reduce your awareness of the passing of time and keep you on the floor, surrounded by opportunities to lose money. There are no clocks or windows in most casinos, and it's hard to find an exit.
One of the cognitive difficulties we encounter with sleep deprivation is an inability to assess our cognitive difficulties. The sleep-deprived just can't recognize the effects of sleep deprivation. So the likelihood of making risky decisions increases. This situation is especially dangerous in professions that offer little margin for error, such as law enforcement, heavy industry, health care or fire and rescue.
Compared with those who get seven or eight hours of sleep per night for a week, those who sleep only five hours a night make riskier decisions, pay less attention to negative consequences and focus more on short-term gains [source: Stevens]. While normally we approach risk in a defensive manner -- guarding against losses -- sleep deprivation makes us more likely to go for the gains confidently and disregard other consequences. In other words, we're more likely to place a large bet at the roulette table and let it ride.
Read on for lots more information about sleep deprivation that may keep you up.