A multi-institutional team of researchers conducted the first study to evaluate how the duration of nightly sleep early in the semester affects first year college students’ end-of-semester grade point average (GPA), Using Fitbit sleep trackers, they found that students on average sleep 6.5 hours a night, but negative outcomes accumulate when students received less than six hours of sleep a night. The results are available in the Feb. 13 issue of the Proceedings of the National Academy of Sciences.

Sleep guidelines recommend teenagers get 8 to 10 hours of sleep every night. Many college students experience irregular and insufficient sleep.

David Creswell, the William S. Dietrich Ⅱ Professor in Psychology and Neuroscience at the Dietrich College of Humanities and Social Sciences, led a team of researchers to evaluate the relationship between sleep and GPA.“Animal studies have shown how critical sleep is for learning and memory,” said Creswell.“Here we show how this work translates to humans.The less nightly sleep a first year college student gets at the beginning of the school term predicts lower GPA at the end of the term. Lack of sleep may be hurting students’ ability to learn in their college classrooms.”

The study evaluated more than 600 first-year students across five studies at three universities. The students wore wrist Fitbit devices to monitor and record their sleep patterns. The researchers found that students in the study sleep on average 6.5 hours a night.More surprisingly, the researchers found that students who receive less than six hours of sleep experienced a pronounced decline in academic performance. In addition, each hour of sleep lost corresponded to a 0.07 decrease in end-of-term GPA.

“Once you start dipping(下降)below six hours, you are starting to accumulate massive sleep debt that can impair a student’s health and study habits, compromising the whole system,” said Creswell.“Most surprising to me was that no matter what we did to make the effect go away, it persisted.”

Five Nutrition Myths and What Health Experts Want You to Know Instead

If you’re looking to improve your diet and achieve your health goals, keep reading to find out what you need to know.

MYTH 1: All fat is bad.

By the 1980s, doctors, government health experts, the food industry and the media were reporting that a low-fat diet could benefit everyone. As a result, many people replaced calories from fat with calories from refined carbohydrates such as white flour and added sugar. 【小题1】 Examples of those include monounsaturated (单元不饱和的) fats found in olive oil, certain nuts and seeds.

MYTH 2: 【小题2】

While the nutrition of plant-based drinks can vary, many have more added ingredients which can contribute to poor health than cow’s milk. Typically, cow’s milk has about eight grams of protein per 250 millilitres. Almond drinks on the other hand, typically has one or two grams in the same amount.

MYTH 3: Potatoes are bad for you.

Potatoes have often been defamed in the nutrition community because of their high glycemic index (血糖指数), which can increase your blood sugar sharply. 【小题3】 They are also inexpensive and available year-round in grocery stores.

MYTH 4: “Calories in, calories out” is the most important factor for maintaining weight.

【小题4】 But research does not suggest that eating more will result in becoming overweight or obese. Rather, it’s the types of foods we eat that may be the long-term drivers of those conditions.

MYTH 5: Fresh fruits and vegetables are always healthier than canned, frozen or dried varieties.

     Research has found that frozen, canned and dried fruits and vegetables can be just as nutritious as their fresh counterparts. 【小题5】 However, some canned, frozen and dried varieties contain added sugars, saturated (饱和的) fats and sodium, so be sure to read nutrition labels, especially on prepared foods.

Drinking more water is an excellent goal for your health. Water is also a calorie-free choice, so drinking more water can help you to lose weight or keep a healthy weight. 【小题1】

Always having water on hand makes it easier to remember to drink it. It’s important to drink more water any time you’ve been sweating, such as when you’re exercising or after spending time in a hot environment. 【小题2】

Drinking water before your meals and while you eat can help to reduce your appetite since thirst is often confused with hunger. 【小题3】 This will save your money when you eat out and help you cut calories.

【小题4】 Try filling up a water bottle and adding a few simple fruit slices such as orange, lemon or some fresh berries such as blueberries, strawberries. Then, let the water sit in the refrigerator for 1-2 hours while it absorbs the flavors.

Tracking the amount of water you drink each day also works. This will help you to determine how much water you’re drinking and figure out if you might need to increase your intake. Remember to set a goal for how much water you want to drink each day. 【小题5】 The amount of water you need depends on your weight, sex, activity level, environment, and other factors. Consider how much of your daily fluid intake is water and identify how much of it you’d like to be water.