People often discuss the dangers of too much stress, but lately a very different view of stress is gaining popularity: this view of stress, held by members of the positive stress movement, argues that stress might actually be beneficial. The positive stress movement is made up of people such as Zachary Rapp who are looking for an edge in a competitive world, and Rapp’s routine is a good example of followers of the movement. He wakes up most mornings at dawn, goes for a run, sips black coffee while ripping through emails, and then steps into a freezing cold shower. This is a routine designed to reduce the stress of running simultaneously three different health and biotechnology companies for 18 hours a day.

        Although Rapp’s practices may sound extreme, he is part of a growing movement, consisting largely of tech industry workers who claim that such radical tactics will help them live better and longer. Inspired by influential figures in different fields, including entertainers, athletes, entrepreneurs and scientists, positive stress practitioners seek out some combination of extreme temperatures, restrictive diets, punishing exercise routines and general discomfort.

        Rapp argues that positive stress keeps him balanced. In addition to running and freezing showers, Rapp uses ice baths, hot yoga, and unconventional eating practices such as eliminating dairy, sugar, alcohol, and various other foods high in carbohydrates. He believes that these practices, which put stress on his body, actually make him feel less stress from work. However, Rapp does not credit anyone in particular for his choices: he said he started using these methods in college, where he got into the habit of taking ice baths to recover from sports. He got back into it while trying to get his three companies off the ground.

        Rapp works long hours and sleeps only five to seven hours a night but he said he only gets sick once a year. For him, the difference between day-to-day stress, like the kind we feel when moving apartments, and positive stress is that the latter involves pushing the body to extremes and forcing it to build up a tolerance.

        One thought leader in the positive stress world is Dutch extreme athlete Wim Hof, who earned the name “ice man” for his ability to withstand severe cold using deep breathing exercises. Hof’s ideas have become popular among tech industry elites and, thanks to Hof, cold showers are now a trend; indeed, some even call it a form of therapy.

        But it is important to note that not everyone agrees with these practitioners; indeed, some medical professionals argue that positive stress is not for everyone, and that it might even be dangerous for people who are unhealthy or older.

解析：D。根据题目中的followers of the positive stress movement和practice可定位至第二段第一句，该句表示，尽管拉普的做法听起来可能有些极端（extreme），但他是这场日益壮大的运动的一部分，该运动的参与者主要是科技从业人员，他们声称，这种激进的策略（tactics）将帮助他们活得更好、更长久。第二句最后还说到，积极压力实践者寻求的是极端（extreme）温度、限制饮食以及全身不适相结合。由此得知，积极压力运动的追随者通常采用激进、极端的做法来把他们的想法付诸实践。D项中的extreme和tactics为原词复现，符合文意，故为正确答案。

错项排除：原文中多次提到了拉普的极端生活习惯，但在原文中未提及积极压力运动的追随者的生活习惯不断改变，故A项排除。B项利用原文中出现的influential figures做干扰，但原文说的是受不同领域有影响力人物的启发，积极压力实践者寻求极端温度、限制饮食、惩罚性锻炼和全身不适相结合的方式，并不是说他们通过与有影响力的人物交往来把他们的想法付诸实践，故排除。C项利用原文中出现的tech industry作干扰，但原文说的是该运动的参与者主要是科技从业人员，并不是说他们通过在科技行业寻找工作来把想法付诸实践，故排除。