VOA健康报道2023--Ice Baths Popular, But Health Claims Not Supported by Evidence

Ice Baths Popular, But Health Claims Not Supported by Evidence

Ice baths are a popular subject on American social media pages. Kim Kardashian, Harry¹ Styles, Kristen Bell, Lizzo, and other stars have posted about their cold water experiences.

Health claims surrounding ice baths include improved mood, increased energy, weight loss and reduced inflammation. But the science linked to some of those claims is not very strong.

Here is what medical evidence, experts and fans say about cold water baths, an activity that dates back hundreds of years.

The mind

Since June 2020, Dan O'Conor has jumped into Lake Michigan almost daily. The 55-year-old man lives in the city of Chicago.

O'Conor used the term endorphins - "feel good" hormones³ released in reaction to pain, stress, exercise and other activities – to talk about his experience.

"The endorphin rush ... is an incredible way to wake up and just kind of shock the body and get the engine going," he said on a recent morning when the air temperature was minus-5 Celsius⁴.

With the lake temperature at 1 degree Celsius, O'Conor did a running jump into the icy gray water.

His first jump came early in the pandemic. O'Conor had too much alcohol and his wife was angry at him. She told him to "go jump in the lake." The common saying is not usually received as a real command.

But, O'Conor acted on it.

He says the water felt good that June day, so he kept jumping in every day following. As the water grew colder with seasonal⁵ change, the good effect was even greater, he said.

"My mental health is a lot stronger, a lot brighter. I found some zen down here coming down and jumping into the lake and shocking that body," O'Conor said.

Dr. Will Cronenwett of Northwestern University's Feinberg medical school tried cold-water immersion⁶ once while visiting Scandinavian friends. After a sauna, he jumped into the ice-cold water for a few minutes. He said it was a powerful experience.

But Cronenwett says studying cold water immersion with a kind of scientific study known as a randomized controlled trial is difficult. This is because it is hard to develop a placebo⁷ for cold water baths.

A placebo is something that has no effect. Placebos⁸ are important because scientific tests need to compare the possible effect of something with something else that does not have any physical effect.

Possible effects on the mind

There are a few ideas about how cold water immersion affects the mind.

Cronenwett says it makes the part of the nervous system that controls the resting state more active. Such an effect may increase feelings of well-being⁹.

Cold water immersion also affects the part of the nervous system that controls the fight-or-flight stress reaction. Cold water treatment on a usual basis may reduce that reaction. So, Cronenwett said, it might help people feel better able to deal with other stresses in their lives, although that is not proven.

Czech researchers found that cold water immersion can increase blood levels of dopamine — another hormone² — by 250 percent. High amounts have been linked with paranoia¹⁰ and aggression¹¹, noted¹² James Mercer of the Arctic University of Norway. Mercer co-wrote a recent scientific paper that examined studies on the treatment.

The heart

Cold water immersion raises blood pressure and increases stress on the heart. Studies have shown this is safe for healthy people and the effects are only temporary.

But sometimes these effects can cause the heart to beat unevenly¹³ and can cause death, Cronenwett said. People with heart conditions or a family history of early heart disease should talk with a doctor before doing cold water immersion, he said.

Metabolism¹⁴

Repeated cold-water immersions during colder seasons have been shown to improve how the body reacts to insulin, a hormone that controls blood sugar levels, Mercer noted.

This might help reduce the risk of getting diabetes¹⁵. It also might help people with the disease control it. More study is required to know for sure.

Cold water immersion also activates¹⁶ brown fat. This tissue helps keep the body warm and helps it control blood sugar and insulin levels. It also helps the body burn calories.

Words in This Story

hormone – n. a natural substance that is produced in the body and that influences the way the body grows or develops

zen – n. a state of peace and calm

immersion – n. the act of putting someone or something completely in a liquid or the state of being completely in a liquid

sauna – n. a special heated room in which people sit or lie down in order to get hot and sweat

stress – n. a physical, chemical, or emotional factor that causes bodily or mental tension and may be involved in causing some diseases

paranoia – n. an unreasonable¹⁷ feeling that people are trying to harm you, do not like you, etc.

calorie – n. an amount of food having an energy-producing value of one large calorie

1 harry   

vt.掠夺，蹂躏，使苦恼

参考例句：

• Today,people feel more hurried and harried.今天，人们感到更加忙碌和苦恼。
• Obama harried business by Healthcare Reform plan.奥巴马用医改掠夺了商界。

2 hormone   

n.荷尔蒙，激素，内分泌

参考例句：

• Hormone implants are used as growth boosters.激素植入物被用作生长辅助剂。
• This hormone interacts closely with other hormones in the body.这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。

3 hormones   

n. 荷尔蒙，激素 名词hormone的复数形式

参考例句：

• This hormone interacts closely with other hormones in the body. 这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。
• The adrenals produce a large per cent of a man's sex hormones. 肾上腺分泌人体的大部分性激素。

4 Celsius   

adj.摄氏温度计的，摄氏的

参考例句：

• The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
• The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。

5 seasonal   

adj.季节的，季节性的

参考例句：

• The town relies on the seasonal tourist industry for jobs.这个城镇依靠季节性旅游业提供就业机会。
• The hors d'oeuvre is seasonal vegetables.餐前小吃是应时蔬菜。

6 immersion   

n.沉浸；专心

参考例句：

• The dirt on the bottom of the bath didn't encourage total immersion.浴缸底有污垢，不宜全身浸泡于其中。
• The wood had become swollen from prolonged immersion.因长时间浸泡，木头发胀了。

7 placebo   

n.安慰剂；宽慰话

参考例句：

• The placebo has been found to work with a lot of different cases.人们已发现安慰剂能在很多不同的病例中发挥作用。
• The placebo effect refers to all the observable behaviors caused by placebo.安慰剂效应是指由安慰剂所引起的可观察的行为。

8 placebos   

n.（给无实际治疗需要者的）安慰剂( placebo的名词复数 )；安慰物；宽心话；（试验药物用的）无效对照剂

参考例句：

• But, eventually, I think they were just kind of like placebos. 但是后来，我想它们只是安慰剂（安慰剂：没有任何药效的药） 来自电影对白
• But comparable numbers of those who received placebos also improved. 但是吃安慰剂的人的病情也改善了。 来自互联网

9 well-being   

n.安康，安乐，幸福

参考例句：

• He always has the well-being of the masses at heart.他总是把群众的疾苦挂在心上。
• My concern for their well-being was misunderstood as interference.我关心他们的幸福，却被误解为多管闲事。

10 paranoia   

n.妄想狂，偏执狂；多疑症

参考例句：

• Her passion for cleanliness borders on paranoia.她的洁癖近乎偏执。
• The push for reform is also motivated by political paranoia.竞选的改革运动也受到政治偏执狂症的推动。

11 aggression   

n.进攻，侵略，侵犯，侵害

参考例句：

• So long as we are firmly united, we need fear no aggression.只要我们紧密地团结，就不必惧怕外来侵略。
• Her view is that aggression is part of human nature.她认为攻击性是人类本性的一部份。

12 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

13 unevenly   

adv.不均匀的

参考例句：

• Fuel resources are very unevenly distributed. 燃料资源分布很不均匀。
• The cloth is dyed unevenly. 布染花了。

14 metabolism   

n.新陈代谢

参考例句：

• After years of dieting,Carol's metabolism was completely out of whack.经过数年的节食，卡罗尔的新陈代谢完全紊乱了。
• All living matter undergoes a process of metabolism.生物都有新陈代谢。

15 diabetes   

n.糖尿病

参考例句：

• In case of diabetes, physicians advise against the use of sugar.对于糖尿病患者，医生告诫他们不要吃糖。
• Diabetes is caused by a fault in the insulin production of the body.糖尿病是由体內胰岛素分泌失调引起的。

16 activates   

使活动，起动，触发( activate的第三人称单数 )

参考例句：

• Activates the window and displays it in its current size and position. 激活窗口，保持当前的大小及位置不变。
• Pulling out the alarm switch activates alarm and pushing it deactivates it. 闹钟的开和关是通过拔出和按入闹铃开关实现的。

17 unreasonable   

adj.不讲道理的，不合情理的，过度的

参考例句：

• I know that they made the most unreasonable demands on you.我知道他们对你提出了最不合理的要求。
• They spend an unreasonable amount of money on clothes.他们花在衣服上的钱太多了。