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Tired? Why you need more sleep and how to get it

However you sleep, we all need it, Dr. Jeanne Duffy says.

For some, all they want to do after a hard day’s work is get a good night’s rest. For others, sleep is a challenge, but as a Harvard educator advises, there are measures anyone can take to improve sleep length and quality.

Dr. Jeanne Duffy, an associate professor of medicine at Harvard Medical School, joined “Take Care” to talk about sleep, the results of getting too little and how to get enough.

Duffy, who is also a neuroscientist in the Division of Sleep and Circadian Disorders in the Departments of Medicine and Neurology at Brigham and Women’s Hospital, said sleep is crucial to being able to function properly when awake.  

Mentally, it allows us to be alert and attentive when we are awake the next day. It helps consolidate new information that we have learned and prunes useless information, strengthens important information and gets rid of unimportant information in our memory. Sleep is also important for our metabolism, immune system and cardiovascular health, Duffy said.

“The more we study sleep, the more we learn about what sleep does for us, both mentally and physically,” Duffy said. “There’s really a whole lot of things that sleep does for us, and we mostly learn about that when people aren’t sleeping and we see what the deficits that come from that are.”

Not getting enough sleep can have numerous consequences, Duffy said, from lowering one’s immune system to impacting metabolism. This can result in higher vulnerability to colds and an increased risk of weight gain.

"Just that worrying about whether you're going to be able to sleep or get a good night's sleep can actually then interfere your sleep itself when you try to go to sleep."

Duffy said how sleep looks today is not the same as it looked hundreds of years ago, which is largely thanks to artificial light from electricity.

“What we can do now that we couldn’t do hundreds of years ago is keep the lights and entertainment systems on 24/7, so our patterns of sleep have changed, and we also think the duration of sleep has changed, because of our access to electricity,” Duffy said. “Sleep and wakefulness were more tied to the natural light/dark cycle than they are now.”

That technology is one of the many things that can disrupt sleep, Duffy said. There are currently dozens of devices designed to measure sleep, including length and type, and Duffy said this technology is a double-edged sword.

For starters, the data from wearable devices can be largely incorrect, especially when compared to the gold standard of sleep tests, polysomnography.

“The short answer is we don’t know how accurate they are, but we do know in some cases, they’re quite inaccurate,” Duffy said.  

Along with inaccuracies, obsessing or worrying about getting enough sleep can actually make one’s sleep patterns worse, she said. People who focus too much on the data and improving it can often stand in their own way.

“They’re already concerned about whether they’re getting enough, and then, they have this information that may or may not be accurate but that’s giving them a number every morning and making them worry about whether the number’s bigger enough,” Duffy said. “And then, just that worrying about whether you’re going to be able to sleep or get a good night’s sleep can actually then interfere your sleep itself when you try to go to sleep.”

Thus, Duffy suggests being cautious when it comes to using such technology -- only use it for comparison purposes and for helping you get more sleep, not less.

Technology is not the only thing that can affect sleep. In general, problems affecting sleep fall into behavioral or medical categories. Behaviors that interfere with sleep include consuming too much caffeine and keeping an irregular sleep schedule. Many like to get more sleep on weekends, for example, which Duffy said is still harmful because it results in an inconsistent sleep/wake cycle.

"Our biological clock is regulated, in part, by our exposure to light and darkness, so by going to bed and getting up at the same time every day, we can keep that clock synchronized."

Medical problems that interfere with sleep include medication side effects and medical disorders like insomnia and sleep apnea. Unfortunately, these can be a bit harder to catch, Duffy said.

“The problem with a lot of sleep disorders is the person who has them is typically not aware of them,” Duffy said. “They only thing that they’re aware of is when they get up in the morning, they don’t feel refreshed, and they may feel sleepy during the day.”

For those on a schedule that does not allow them to sleep at night, they face their own set of issues because they disrupt their body’s natural clock. Many with this sleep schedule develop shift work disorder, Duffy said, where shift workers try to overcome the natural sleep/wake schedule to sleep during the day and work at night. This can result in trouble falling and staying asleep because the body naturally prefers to sleep at night.

“What happens with long-term shift workers is that they are typically only sleeping about five to six hours of sleep a night, night after night, year after year,” Duffy said. “And they do have higher rates of some medical problems.”

These problems can range from an increased risk of cancer to strain on the metabolic and cardiovascular systems, Duffy said. That is why it is important to try to adhere to a normal sleep/wake cycle.

How long sleep lasts in that cycle can vary to person to person, especially depending on age, Duffy said. From childhood to adulthood, the amount of sleep needed decreases substantially, but the same cannot be said from early to late adulthood, she said.

Many teenagers and adults proclaim they can function just fine on three to five hours of sleep, but that does not mean they are actually getting enough, Duffy said. Though the amount of sleep each person needs varies, most adults need seven to nine hours per night.

“There are certainly individual differences, and it is a very rare and unusual person who can function at their best at three or four or five hours of sleep,” Duffy said.

Duffy said that studies have shown that even those that say little sleep works for them are quite sleep deprived. This means that everyone needs a full night’s rest, regardless of how well a person perceives their performance after just a few hours’ rest.

Getting enough sleep requires proper sleep hygiene, Duffy said, which are the practices surrounding sleep that can make it better or worse. If you are having trouble falling asleep, cut down on caffeine and consume it earlier in the day. Similarly, regular exercise can improve sleep but disrupt sleep if the workout is done too close to bedtime.

The best practice that improves sleep, Duffy said, is simply to have a regular bed and wake time. That consistency means there is a set time out of our day for sleep, and adhering to it helps us reap all the health benefits of a full night’s rest.

“Our biological clock is regulated, in part, by our exposure to light and darkness, so by going to bed and getting up at the same time every day, we can keep that clock synchronized, and then, it will be promoting sleep when we go to bed every night consistently and helping us to stay awake during the daytime,” Duffy said.