第1893期:How the seasons affect your sleep

After a long winter, the arrival of spring can be a welcome relief. The days grow longer, the temperatures increase, and the natural world around us comes to life again. But when the seasons change, our sleep patterns change with them.

经过漫长的冬天，春天的到来可以让人感到欣慰。 白天变长，气温升高，我们周围的自然世界又恢复了生机。 但当季节变化时，我们的睡眠模式也会随之改变。

New research suggests that humans may need more sleep in the winter than they do in the summer. A German study found that participants slept an hour longer in December than in June, regardless of their exposure to light. "Our study shows that even while living in an urban environment, with just artificial light, humans [experience] seasonal sleep," says Dieter Kunz, one of the study's lead authors and head of the clinic of sleep and chronomedicine at St Hedwig Hospital in Berlin, Germany. The study found that the participants experienced seasonal variations in their rapid eye movement sleep, also known as REM sleep, as well as in their slow wave sleep, also known as deep sleep. REM sleep, which is when we dream and our heart rate increases, was 30 minutes longer in the winter than during the summer. Slow wave sleep, which is when our muscles are repaired, our immune system is strengthened and our memory is consolidated, was 30 minutes shorter in September than in February.

新的研究表明，人类在冬天可能比夏天需要更多的睡眠。 德国的一项研究发现，参与者在 12 月的睡眠时间比 6 月长一个小时，无论他们接触的光线如何。 “我们的研究表明，即使生活在只有人造光的城市环境中，人类也会经历季节性睡眠，”该研究的主要作者之一、德国柏林圣海德维医院睡眠和时间医学诊所负责人迪特·昆茨 (Dieter Kunz) 说。 研究发现，参与者的快速眼动睡眠（也称为快速眼动睡眠）和慢波睡眠（也称为深度睡眠）经历了季节性变化。 快速眼动睡眠（即我们做梦且心率加快的时间）在冬天比夏天长 30 分钟。 慢波睡眠是指我们的肌肉得到修复、免疫系统得到增强、记忆得到巩固的时间，9 月份比 2 月份短了 30 分钟。

But why do our bodies and brains need more rest at certain times of year? The answer could lie in our evolutionary past. That's according to Neil Stanley, who's a sleep expert at Sleep Station, an online provider of cognitive behavioural therapy for insomnia. "We have evolved to dark-light cycles, so when we wake up on a winter's morning and it's dark, our brain is going 'I can't do anything… there's no point leaping out of bed.'" Particularly in summer, temperature also plays a role – our bodies require a skin temperature of between 31-35 degrees centigrade [Celsius] for a good night's sleep, but this can be harder to control during the warmer months.

但为什么我们的身体和大脑在一年中的某些时候需要更多的休息呢？ 答案可能在于我们的进化史。 这是睡眠站 (Sleep Station) 的睡眠专家尼尔·斯坦利 (Neil Stanley) 的说法，该站是一家针对失眠的认知行为疗法的在线提供商。 “我们已经进化到了暗光循环，所以当我们在冬天的早晨醒来时，天很黑，我们的大脑会说‘我无能为力……从床上跳起来是没有意义的。’”特别是在夏天，温度也发挥着重要作用——我们的身体需要 31-35 摄氏度之间的皮肤温度才能睡个好觉，但在温暖的月份里这可能更难控制。

Of course, nowadays, it is our school and work times – not the Sun – that determine when we get up in the morning. But, as autumn approaches, it seems we now have a good excuse for an early night.

当然，如今，决定我们早上何时起床的是我们的上学和工作时间，而不是太阳。 但是，随着秋天的临近，我们似乎有了早睡的好借口。

词汇表

relief （不快后的）解脱
come to life 复苏，恢复生机
sleep pattern 睡眠模式
exposure to 接触
artificial light 人造光
seasonal sleep 季节性睡眠
chronomedicine 时间医学
variation 变化
rapid eye movement sleep 快速眼动睡眠
slow wave sleep 慢波睡眠
deep sleep 深度睡眠
repair 修复
immune system 免疫系统
consolidate 加强，加固
rest 休息
cognitive behavioural therapy 认知行为疗法
insomnia 失眠
evolve 逐渐进化
dark-light cycle （昼夜）光暗循环
leap out of bed 跳下床，起床
early night 早睡