眾所周知，晚睡晚起不利於身體健康，但還是有很多人喜歡當「夜貓子」。新研究發現，夜貓子對胰島素的抵抗性更強，新陳代謝燃燒的脂肪也更少，這會增加患2型糖尿病和心臟病的風險。
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If you prefer to go to bed and get up later – a sleep chronotype known as being a night owl – you may be at higher risk for type 2 diabetes and heart disease, a new study found.
一項新研究發現，如果你喜歡晚睡晚起的夜貓子睡眠模式，你患2型糖尿病和心臟病的風險可能會更高。
Night owls were more sedentary, had lower aerobic fitness levels and burned less fat at rest and while active than early birds in the study. Night owls were also more likely to be insulin-resistant, meaning their muscles required more insulin to be able to get the energy they need, according to the study published Monday in the journal Experimental Physiology.
這項於9月19日發表在《實驗生理學》期刊上的研究指出，相比早起的人，夜貓子更不愛動、體能更差、休息和活動時燃燒的脂肪也更少。夜貓子對胰島素的抵抗性也更強，這意味著他們的肌肉需要更多胰島素才能獲得自身所需的能量。
"Insulin tells the muscles to be a sponge and absorb the glucose in the blood,」 said senior study author Steven Malin, an associate professor in the department of kinesiology and health at Rutgers University in New Jersey.
該研究的資深作者、美國新澤西州羅格斯大學運動技能與健康學副教授史蒂芬·馬林說：「胰島素讓肌肉像海綿一樣吸收血液中的葡萄糖。」
"Think about it like water from a water faucet: You turn the water on and a drop touches the sponge and is immediately absorbed,」 Malin said. 「But if you’re not exercising, engaging those muscles, it’s like if that sponge was to sit for a couple days and get rock hard. A drop of water isn’t going to make it soft again.」
「你可以將其想像成水龍頭裡流出的水：你打開水龍頭，一滴水落到海綿上，立刻就被吸收了。但是如果你沒有鍛鍊和使用你的肌肉，就像把海綿放了兩三天，已經變硬了。這時候一滴水就無法讓海綿重新變軟。」
If sleep chronotype is affecting how our bodies use insulin and impacting metabolism, then being a night owl might be useful in predicting a person’s risk for heart disease and type 2 diabetes, Malin added.
馬林指出，如果睡眠類型會影響人體使用胰島素以及新陳代謝的方式，那麼夜貓子習性便可以用來預測一個人患心臟病和2型糖尿病的風險。
Sleep chronotype can have profound effects on productivity, school performance, social functioning and lifestyle habits, experts say. Early birds tend to perform better in school, and are more active throughout the day, which may partly explain why studies have found they have less risk of cardiovascular disease, Malin said.
馬林稱，睡眠類型對工作效率、學業成績、社交能力和生活習慣都會產生深遠影響。早起的人通常在學校表現更好，白天也更活躍，這在某種程度上可以解釋為什麼研究發現早起的人患心血管疾病的風險更低。
Evening types may take more risks, use more tobacco, alcohol and caffeine, and are more likely to skip breakfast and eat more later in the day. In addition, research suggests 「later cronotypes have higher body fat located more in the stomach or abdominal region, an area which many health professionals believe to be worse for our health,」 Malin said.
馬林表示，夜貓子患心血管疾病的風險則更高，他們攝入的菸酒、咖啡因都更多，而且更可能不吃早飯，在午飯和晚飯時大吃大喝。此外，研究還表明，「夜貓子在腹部囤積的脂肪更多，許多健康專家都認為這塊區域脂肪堆積不利於健康」。
Researchers classified 51 adults without heart disease or diabetes into morning or evening chronotypes, based on their natural sleep and wake preferences. During the study, the participants ate a controlled diet and fasted overnight while their activity levels were monitored for a week.
研究人員將51名沒有心臟病或糖尿病的成年人基於天生睡眠喜好分成早起者和夜貓子兩組。這些研究參與者在一周時間內控制飲食並在夜裡禁食，與此同時研究人員對他們的活動水平進行監測。
The research team determined each person’s body mass, body composition and fitness level, and measured levels of insulin sensitivity. In addition, researchers looked at how each person’s metabolism obtained most of their energy, either via fat or carbohydrates.
研究團隊測量了每個人的體重指數、身體成分和體能水平，以及對胰島素的敏感度。除此以外，研究人員還查看了每個人是從脂肪還是碳水化合物中獲取新陳代謝所需的大部分能量。
"Fat metabolism is important because we think if you can burn fat for energy that’s going to help the muscle pick up the glucose in a more enduring fashion,」 Malin said.
馬林說：「脂肪代謝很重要，因為我們認為，如果你可以通過燃燒脂肪獲取能量，就可以幫助肌肉更持久地吸收葡萄糖。」
Burning fat can promote endurance and more physical and mental activity throughout the day. Carbohydrates, on the other hand, are what the body uses for intense physical activity. Carbs are burned more quickly, which is why many athletes carb-load in advance of a race or marathon.
燃燒脂肪可以增強一個人的耐力，讓其有精力在一天中開展更多體力和腦力活動。身體在進行劇烈運動時則會燃燒碳水化合物。碳水化合物燃燒得更快，這就是為什麼許多運動員在比賽或馬拉松長跑前要攝入充足的碳水化合物。
Results of the test showed early birds used more fat for energy at both rest and during exercise than night owls in the study, who used more carbohydrates as a source of fuel.
測試結果顯示，早起的人在休息和運動時燃燒的脂肪比夜貓子更多，而夜貓子則會燃燒更多碳水化合物來獲取能量。
英文來源：美國有線電視新聞網
翻譯&編輯：丹妮
來源：中國日報網
