By now it's almost common knowledge that spending time in nature is good for you. Areas with more trees tend to be less polluted, so spending time there allows you to breathe easier. Spending time outdoors has been linked with reduced blood pressure and stress, and seems to motivate people to exercise more.

“So it'll come as no surprise that there's research showing that spending time in nature is good. I mean, that's been known for millennia. There's dozens of papers showing that. "University of Exeter Medical School researcher Mathew P. White." We get this idea, patients are coming to us and they're saying, 'doctor, how long should I spend?' and the doctor is saying, 'I don't really know.'"

So White and his team decided to find out by using data collected from nearly 20,000 people in England through the Monitor of Engagement with the Natural Environment Survey. And their answer? Two hours a week. People who spent at least that much time amid nature - either all at once or totaled over several shorter visits - were more likely to report good health and psychological well-being than those with no nature exposure.

Remarkably, the researchers found that less than two hours offered no significant benefits. So what's so special about two hours? "I have absolutely no idea, really. We didn't have an a priori guess at what this would be, this threshold. It emerged. And I'd be lying if I said we predicted this, I don't know."

Even more noteworthy, the two-hour benchmark applied to men and women, to older and younger folks, to people from different ethnic backgrounds, occupational groups, socioeconomic levels, and so on. Even people with long term illnesses or disabilities benefited from time spent in nature - as long as it was at least 120 minutes per week. The study is in the journal Scientific Reports.

While the findings are based on a tremendous number of people, White cautions that it’s really just a correlation. Nobody knows why or how nature has this benefit, or even if the findings will stand up to more rigorous investigation.

"I want to be really clear about this. This is very early stages. We're not saying everybody has to do 120. This is really to start the conversation, saying, what would a threshold look like? What research do we need to take this to the next step before doctors can have the true confidence to work with their patients? But it's certainly a starting point."

Adapted from https://www.chinavoa.com/show-8762-241768-1.html

1. millennia n. 一千年（millennium的名词复数）

2. a priori adj. (from Latin, formal) using facts or principles that are known to be true in order to decide what the probable effects or results of sth. will be, for example saying ‘They haven't eaten anything all day so they must be hungry. ’从事实推断结果；由因及果

3. threshold n. the level at which sth. starts to happen or have an effect 阈；界；起始点。例如:

He has a low boredom threshold (= he gets bored easily). 他极易感到乏味。

I have a high pain threshold (= I can suffer a lot of pain before I start to react). 我的痛阈很高。

My earnings are just above the tax threshold (= more than the amount at which you start paying tax). 我的收入刚刚超过征税起点。

4. benchmark n. something which can be measured and used as a standard that other things can be compared with 基准。例如：Tests at the age of seven provide a benchmark against which the child's progress at school can be measured. 七岁时进行的测试为孩子在学校中的学习发展提供了一个测量基准。

5. stand up to sth. : (of materials, products, etc. 材料、产品等) to remain in good condition despite rough treatment 能承受，经受得住，耐（…） withstand 例如：The carpet is designed to stand up to a lot of wear and tear. 这种地毯设计得十分耐用。

6. rigorous adj. demanding that particular rules, processes, etc. are strictly followed 严格的；严厉的 strict 例如：The work failed to meet their rigorous standards. 工作没有达到他们的严格标准。

1. Spending time outdoors has been linked with reduced blood pressure and stress.

2. Research shows that spending time in nature is good. 

3. White and his team decided to find out by using data collected from nearly 20,000 people in Scotland through the Monitor of Engagement with the Natural Environment Survey. 

4. Even more noteworthy, the two-hour benchmark applied to men and women, to older and younger folks, to people from different ethnic backgrounds, occupational groups, socioeconomic levels, and so on. 

5. Even people with long term illnesses or disabilities didn’t benefit from time spent in nature. 

6. Somebody knows why or how nature has this benefit, or even if the findings will stand up to more rigorous investigation.

√1. Spending time outdoors has been linked with reduced blood pressure and stress.

√2. Research shows that spending time in nature is good. 

×3. White and his team decided to find out by using data collected from nearly 20,000 people in Scotland through the Monitor of Engagement with the Natural Environment Survey. White and his team decided to find out by using data collected from nearly 20,000 people in England through the Monitor of Engagement with the Natural Environment Survey. 

√4. Even more noteworthy, the two-hour benchmark applied to men and women, to older and younger folks, to people from different ethnic backgrounds, occupational groups, socioeconomic levels, and so on. 

×5. Even people with long term illnesses or disabilities didn’t benefit from time spent in nature. Even people with long term illnesses or disabilities benefited from time spent in nature. 

×6. Somebody knows why or how nature has this benefit, or even if the findings will stand up to more rigorous investigation. Nobody knows why or how nature has this benefit, or even if the findings will stand up to more rigorous investigation.