热瑜伽和出汗的锻炼已经流行了多年，但是现在寒冷的锻炼也开始露面。至少有一个纽约健身房Brrrn致力于在寒冷条件下（50ºF/10ºC）锻炼的好处，并且这种趋势开始持续下去。因此，它引出了一个问题：在寒冷或热量中训练您是否有意义？
Athletes have long argued hot workouts lead to increased performance, endurance and a higher blood flow and sweat rate. Plus, your muscles are pliable and warm. But the cold training advocates say you work harder in cold temperatures and burn more calories.
哪一个是对的？不同锻炼的最佳温度是多少？
There are two ways to consider temperature, says Christopher Minson, a professor of human physiology at the University of Oregon and an expert on temperature adaptations in athletes:
One, how elite athletes use cold and heat in training, and two, how hot and cold create physiological changes in regular people doing regular things — i e., when you’re not working out.
WHAT HAPPENS TO YOUR BODY IN THE HEAT?
Heat can be used to force some of the same health effects as exercise, says Minson. Periods of heat stress, like time insaunasor hot tubs with temperatures ranging from 100–180ºF, he says, leads to an increase in heart rate and in blood flow to the skin. Your body then adapts to the blood flow, proteins are released and there’s a decrease in inflammation response and oxidation stress.
“Heat stress is very much like exercise,” he says, in terms of the long-term cardiovascular changes. For example, he says,some studieshave shown people who spend more time in saunas over years have better health outcomes: fewer heart attacks, greater longevity and decreased risk of hypertension and Alzheimer’s.
但是，如果您必须在锻炼或坐在桑拿浴室之间进行选择，请选择运动。
The challenge with exercising in the heat at temperatures around 90–100ºF, however, is you get more dehydrated, so it’s harder to work as hard as you would otherwise. That’s why elite athletes do shorter periods of heat acclimation — either doing some of their easy workouts in the heat until they adapt, sitting in hot tubs or saunas after harder workouts at regular temperatures or simply slowly adjusting to the weather. It takes about 7–14 days for the effort level, heart rate and core temperature to adapt to a hotter environment.
有证据表明，经过热适应之后运动员实际上甚至在常规或较冷的温度下表现更好. There are increases in plasma volume and sweat rate, which helps lead to increases in endurance, VO2 max and lactate threshold.
But if you overheat and your core temperature becomes too high, you can experience cognitive dysfunction, which may lead to heat stroke and organ failure. A person’s core temperature hovers right around 98.6ºF (37ºC) and if that goes slightly up or down, the body starts to shut down. In terms of heat, by the time your core temperature hits 102–104ºF (38.8–40ºC), you’ll start to be disoriented. By the time it hits 107ºF (41.6ºC), your body will shut down.
WHAT HAPPENS TO YOUR BODY IN THE COLD?
What happens to your body in the cold is similar to what happens in the heat, says Minson. There is less oxidation and inflammation, some of the same proteins are triggered, and cell damage can be repaired. But the effect on your workouts is slightly opposite — i.e., you’re likely able to work and train harder in the cold. This happens even at moderately cold temperatures of just 45–60ºF, because all that’s necessary is to keep the core body temperature from rising too much, allowing you to work harder.
There has been some research done on the health effects of bouts of cold stress — like ice baths orcryotherapy— but that research is less clear than the research on heat stress. Cold stress triggers what is known as a正常脂肪细胞的米色或褐变, says Minson, making them more metabolically active. There is also some evidence thatpeople who spend lots of time in colder temperaturesburn more calories.One argument表明肥胖症流行与总体温度较高有关，但尚不清楚仅仅洗冰浴还是在寒冷中锻炼，对您的代谢具有相同的一般影响。
在极度寒冷的温度下训练的缺点是它会产生肌肉紧绷，因此您需要保持良好的热量。如果您的核心温度甚至只有几个程度，那么您的身体的适应能力和调整能力较小，而不是加热。您将开始发抖，血液将流向您的核心，然后您将开始慢慢挣扎。
Additionally, we know there are some downsides to decreasing inflammation after every workout. Ice baths, says Minson, reduce muscle soreness and inflammation, but aninflammatory response actually has some long-term benefits, too. Yes, you’ll feel less sore after an ice bath, but the inflammatory response also triggers adaptation and protein synthesis — so getting rid of that after every hard workout makes you less strong in the long run.
IS COLD OR HOT BETTER?
“It’s hard to say what’s better,” says Minson.
一方面，热适应和热锻炼有很多好处，但是您很容易在热量中变得太脱水或挣扎。如果您特别容易过热，那么您也可能会真正讨厌热瑜伽或热跑。
For people who dislike the feel of sweating and heat, then a colder workout might get them working out more often and exercising harder, which results in a larger aerobic benefit. You may also see some increases in calories burned, but it requires you to work hard to maintain a core temperature.
理想的温度因锻炼而异。
Most research on the ideal temperature for working out has been done on running, which can be extrapolated to a number of other activities. However, there are also sport-specific considerations for swimming, biking or gym workouts.
RUNNING
The ideal temperature for running has been studied extensively across many races. Most research suggests the ideal temperature for a long-distance runner is cooler than what feels comfortable just standing around — and for every degree warmer, performance drops significantly.
One studyfound 43.2ºF (6.2ºC) produced the fastest times overall — with the fastest runners benefiting from slightly colder and the midpack runners optimizing their performance a few degrees warmer. Anotherstudy在多个马拉松比赛中，发现非精英赛跑者（3：30–5：00马拉松运动员）的表现较高，约为44ºF（6.6ºC）。一个单独的、长达数十年的研究of the Boston Marathon found the ideal temperature range for all athletes (not just the pros) is 46–59ºF (7.7–15ºC).
If you’re not running a marathon, though, you don’t necessarily want to be that cold. In fact,sprint performance is ideal at significantly warmer conditionsbecause you want your muscles to be warm and power to be at peak, but not so warm as to create higher core temperatures.
游泳
对于奥林匹克竞争，泳池温度的要求在77-82ºF（25–27.7ºC）之间。温暖的水会导致过热和脱水（即使您不觉得自己在水中出汗）。
However, that temperature assumes a vigorous workout. Your core temperature is significantly higher than 82ºF (27.7ºC), though, and you can lose heat through the water. So if you don’t keep swimming to keep your core temperature up, you could certainly get too cold in the water and start shivering. Because your skin temperature is 92ºF (33.3ºC) and temperature receptors are in your skin, it’s also likely the water will feel cold when you jump in.
If you’re going to swim in extremely cold temperatures — like cold water plunges in 50–60ºF (10–15.5ºC) — then you might experience cold shock and have difficulty breathing. That can be followed by a loss of dexterity and the use of your hands and legs. After 20–30 minutes, it’s also possible to experience hypothermia.
BIKING
In many ways, biking is similar to running in terms of cardiovascular output and core temperatures.Studiessuggest there are decreases in time to fatigue and average power output at temperatures above 86ºF (30ºC) when compared to temperatures below 70ºF (21.1ºC).
Those temperatures are slightly higher than with running because you also have to factor in the wind chill. When cycling, you’re moving at a faster speed than running, which causes more cooling effect from the wind. That’s also why cyclists have to dress carefully. If you get wet or start sweating and then slow down, you could get significantly colder.
Some cyclists also find it harder to bike in extremely cold temperatures. Air density is greater at lower temperatures and the resistance or drag at 25ºF (-3.8ºC) is about 10% greater than at 75ºF (23.8ºC).
THE GYM
If you’re hitting the gym and indoor classes, then The American College of Sports Medicine recommends a temperature of 68–72ºF (20–22.2ºC) for indoor cycling studios.
