内容来源：https://lifehacker.com/health/benefits-of-zone-3-cardio?utm_medium=RSS

内容总结：

心率区间3训练被低估：科学视角下的“轻松有氧”新解

近年来，心率区间2（Zone 2）训练因能高效提升有氧基础、促进脂肪燃烧且不易疲劳而备受推崇。然而，当运动时心率自然攀升至区间3，是否意味着训练效果大打折扣？最新运动科学观点指出，事实可能恰恰相反：区间3训练不仅能带来与区间2相似的有益效果，甚至在效率上更具优势。

一、 区间划分的“人为性”：身体感受比数字更真实

主流的心率五区间体系通常基于最大心率的固定百分比划分，但这一划分方式更多出于测量便利，而非精确的生理界限。不同设备对同一区间的定义常存在差异，例如在苹果手表上被归为区间3的心率，在Peloton设备上可能仍属于区间2。科学研究通常依据更个性化的生理指标（如通气阈值、乳酸阈值）来界定强度，而非预设的固定心率区间。

关键生理指标“通气阈值”（VT1），即运动时呼吸开始急促、无法流畅交谈的临界点，通常出现在最大心率的78%左右，这已接近甚至达到了许多体系中心率区间3的上限。这意味着，只要运动强度保持在“能够基本正常交谈”的范围内，其生理效益在区间2与大部分区间3内是连续且相似的。

二、 区间3训练：被误解的“高效有氧区”

将区间2与区间3视为一个连续的“轻松有氧连续体”更为合理。在此范围内，从区间2的低端到区间3的高端，运动者仍在进行有效的有氧工作，持续改善线粒体功能、毛细血管密度等健康指标。与区间2相比，在区间3训练能在单位时间内燃烧更多热量，提升训练的时间效率。

对于训练时间有限的普通人而言，每周进行数次区间3训练，既能获得显著的有氧益处，其疲劳感也远低于高强度间歇训练（HIIT）。在训练实践中，跑者的节奏跑、比赛配速跑及较快速度的“轻松跑”，往往都落在这一区间。自行车手则常称此强度范围为“甜区训练”，因其能在不过度疲劳的前提下有效提升运动能力。

三、 实践指导：如何理性看待心率数据？

心率数据易受多种因素干扰，如气温、疲劳程度、脱水、紧张情绪乃至药物影响，因此不宜过度拘泥于手表显示的区间数字。更可靠的强度判断标准是自身的“谈话测试”和呼吸感受。如果运动时心率显示进入区间3，但呼吸平稳、交谈无碍，那么这次训练依然属于有效的轻松有氧范畴，无需焦虑。

关于减脂与训练安排：

• 减脂效率：区间3单位时间燃脂效率更高。若每周仅运动数次且不介意稍高强度，区间3是理想选择。
• 长期可持续性：若追求每日50-60分钟的运动量以维持减重效果（研究表明此时长效果显著），则混合安排强度更低的区间2训练更易于长期坚持，避免过度疲劳。

四、 结论：摒弃“非此即彼”，追求平衡与个性化

所谓“区间3是应避免的灰色地带”的说法是一种误解，其初衷是提醒运动者不应将所有训练都安排在中高强度，而应遵循“极化训练”原则，将大部分时间（如80%）用于低强度（涵盖区间2及部分区间3），小部分时间（如20%）用于高强度区间4-5的训练。

最终，最佳训练方案取决于个人目标与整体训练量。对于大众健身者而言，无需对偶尔“越界”至区间3感到担忧。将关注点从严格的心率数字，回归到身体的真实感受与可持续的训练节奏上，在区间2与3构成的广阔“有氧基础带”中享受运动，方能获得健康与效率的最大化收益。

中文翻译：

心率区间2训练确实有益，这点你可能早有耳闻。但当你跑步或在健身房进行有氧运动时，心率若飙升至区间3会发生什么？令人意外的是：你并不会因此失去区间2训练的好处。区间3对你同样有益，甚至可能更胜一筹。

要知道，人们推崇区间2训练的原因在于它能帮助建立有氧基础、燃烧热量且不易引发疲劳。而区间3训练呢？没错，它同样能增强有氧基础，燃烧更多热量，且疲劳感通常仅略高于区间2。既然如此，为何我们不更多地采用区间3有氧训练？

区间2被高估了
低强度与高强度训练各有其价值。当前轻松有氧运动正流行，因此人人都在谈论多练区间2。在心率监测设备普及前，人们只能自行判断何为"轻松"，或通过对比跑步速度与比赛配速来评估。非运动员则采用"谈话测试"：若慢跑时能自如交谈，便说明处于轻松稳定的节奏。

但当人人都佩戴能显示心率的手表后，我们开始紧盯具体数值。设备用颜色区分区间，让你清楚自己处于区间2还是3。心率多跳一下？立刻"越界"！简直像被关进训练监狱！

但现实是，心率152次/分与153次/分的训练效果并无天壤之别。甚至145与155次/分之间可能也差异甚微——只要两者都维持在能交谈的强度范围内。

区间划分并非绝对真理
流行的心率区间体系仅为便于测量而设，与身体实际反应并无精确对应关系。运动强度确实存在某些生理临界点（例如无法舒适交谈的时刻，或乳酸累积速度超过清除速度的节点），但这些临界点与常见的五区间体系并不完全吻合。

五区间体系通常以最大心率百分比划分，各区间边界由特定百分比界定：

• 区间1：休息或极低强度
• 区间2：轻松可交谈的节奏
• 区间3：模糊地带（常被误称为应避免的"灰色区间"——我对此不认同！）
• 区间4：相当吃力
• 区间5：极限强度

这个体系构思巧妙且对许多人有益，但并无科学证据证明在最大心率60-70%与71-80%区间会获得截然不同的效益。不同设备对区间的定义就存在差异：Apple Watch的"区间2"可能是60-70%，而Peloton则定义为65%-75%。若心率73%，前者会判定为区间3，后者却认为是区间2。谁正确？其实都不绝对。

运动效益研究并不采用这类心率区间。他们可能通过多种方式衡量强度，例如是否超过通气阈值（基本指运动时能否交谈）或乳酸阈值（通过血液检测，大致指能长期维持的最高强度），有时也采用代谢当量（METs）或摄氧量（VO2max由此而来）。即便研究中使用心率指导，也是基于个体化测量数据，而非应用程序或网络视频中千篇一律的区间划分。

可交谈强度涵盖区间2及大部分区间3
仔细审视"谈话测试"或"可交谈节奏"这个概念：保持有氧运动处于可聊天的强度，其实源于通气阈值这一科学概念。

想象从步行开始，每分钟略微提速。随着强度增加，你会到达呼吸略显急促、说话断断续续的临界点。若此时与朋友交谈，只能断断续续吐几个词，无法流畅讲述故事。这个临界点就是你的通气阈值（简称VT，有时称VT1）。

运动员或教练所说的轻松强度，通常要求低于VT。虽然人们常将区间2与轻松划等号，但实际上可交谈节奏更接近最大心率的80%——这已是区间3的顶端。例如一项针对业余跑者的研究发现，他们的VT1平均出现在最大心率的78%处，且该研究实测了跑者的最大心率（而非采用年龄估算公式——永远别轻信默认公式）。

因此，若你想进行轻松训练，或遵循80/20原则（80%训练保持轻松），完全可以在区间2和3内完成轻松跑或有氧训练，不必局限于区间2。

区间3仍属有氧且依然轻松
既然区间2与3的划分具有随意性，我们更应将区间2和3（甚至1至3）视为连续整体。在较低端，你跑速或踏频较慢，燃烧热量较少，感觉几乎没费力（这就是舒适的"温馨有氧"！）。在较高端（区间3顶端），你仍在进行大量有氧锻炼，持续强化线粒体与毛细血管等功能，但用时更短。若关注每小时热量消耗，区间3效率更高。

自行车手常称此强度范围为"甜区训练"，能在不过度疲劳的前提下获得高强度训练的部分优势。对跑者而言，区间3可能包含节奏跑、比赛配速跑及较快的"轻松跑"。

既然区间3能获得区间2的所有益处，区间2还有何意义？这取决于你的整体规划：若训练量很大，部分训练安排在区间2有助于节省体力以累积里程。但若每周仅运动三次，即使全在区间3训练，也不太可能让你过度疲劳。

不必过度解读心率数据
这让我不得不再次吐槽心率监测设备（这种吐槽源于爱——我跑步时也监测心率并发现其多方面价值）。

心率不仅反映训练强度，还受诸多因素影响：夏季高温会推高心率；疲劳时或训练尾声心率可能升高；轻微脱水也会导致心率上升；比赛开始时因紧张心率可能异常增高；某些药物（如β受体阻滞剂）更会显著降低心率。

此外，健身设备的区间设置是否准确也成问题（即便已知其边界是人为设定的）。若你从未进行过全力冲刺或坡道训练，设备可能从未捕获你的真实最大心率。如果仅因你36岁就断定最大心率为184次/分，这无异于按身高购买平均鞋码而不实际试穿。若轻松跑时心率全程显示"区间5"，那绝非真实情况。如需精确数据，应通过专项测试测定最大心率。

因此，当"区间2训练"时心率漂移至区间3，这个读数未必准确。但即便准确，只要呼吸交谈基本正常，你的区间3有氧训练依然益处良多。

减脂选区间2还是3？
两者皆可！若每周只能进行几次有氧运动且不介意强度，区间3是绝佳选择——它比高强度间歇训练更不易疲劳，又比区间2效果更显著。

但若有更多时间，建议逐步达到每日50-60分钟的运动量（研究显示此时长对减重并维持效果最佳，有趣的是即便不调整饮食也有效）。如此大的运动量若全以区间3完成，多数人会难以承受——而区间2则更易坚持。运动量越大，越需要加入区间2等轻松训练来平衡高强度训练日。

因此，大运动量训练者应安排部分区间2训练，其余可为区间3或更高强度；每周仅运动数日者，区间3或许是更优选择。

最佳有氧心率区间是哪个？
每个区间都有独特价值。若要提升心肺健康，应全面涉足各区间：

• 区间1：适用于热身、冷身及间歇训练的恢复期
• 区间2：适合长时间持续运动，通常可替代休息日
• 区间3：助你适应比区间2更强的负荷，燃脂效率更高但疲劳感略增，也是备战半马等赛事时练习比赛配速的区间
• 区间4：助你逼近乳酸阈值，提升高强度耐力，运动员需重点训练但每周仅安排1-2次
• 区间5：极高强度区间，适合高强度间歇训练（间歇期以区间1强度恢复）

总体而言，应多在低区间训练，并穿插高区间训练增加多样性。按80/20训练原则，80%训练时间应处于区间2及低区间3，高区间3及以上强度仅占每周训练的20%。这虽非唯一训练结构，却是帮助跑者均衡发展的流行方法。

区间3真是毫无益处的"灰色地带"吗？
绝非如此！这个误解源于教练和作者们为纠正"全部训练都应中等强度"的观念而提出的建议——他们主张结合轻松训练（区间2）与高强度训练（区间4练阈值，区间5练间歇）。强调高低两极的"极化训练"理念本意良好，却逐渐演变成"必须避开区间3"的谬传，这完全不符合事实。

英文来源：

There are benefits to training in heart rate zone 2, and you’ve probably heard all about them. But what happens when your heart rate spikes into zone 3, whether when you're on a run or doing cardio at the gym? Surprise: You don’t lose the benefits of zone 2 training. Zone 3 is arguably just as good for you, or maybe even better.
Remember, the reason people are excited about zone 2 training is that it helps you build your aerobic base and burn calories without incurring much fatigue. Guess what zone 3 training also does? Yep, it helps you build your aerobic base, burn even more calories, and usually only incur a tiny bit more fatigue than zone 2. So why aren’t we all doing more zone 3 cardio?
Zone 2 is overrated
There are reasons to run (or do any cardio) at lower intensities, and reasons to use higher intensities. Easy cardio is having a moment right now, so everybody is talking about doing more zone 2. Before heart rate monitors were widespread, you had to judge what was “easy” by yourself, or by comparing your speed of running to what you knew you could do in a race. Non-athletes had the “talk test": If you could hold a conversation while jogging, you knew you were at an easy, steady pace.
But when everybody has a watch that tells them their heart rate, suddenly we’re looking at specific numbers, and our watches color code the numbers so you know when you’re in zone 2 versus zone 3. Your heart ticks up a beat? You’re out of your zone. Straight to workout jail!
But the reality is, your body isn’t getting a drastically different workout at 153 beats per minute than it was at 152. There probably isn’t even much difference between, say, 145 and 155, as long as they’re both within that conversational-ish effort level.
Zones aren’t real
The most popular heart rate zone systems use zones that are divided up for convenient measuring. They don't have any precise relationship to what's going on in your body. Your body does have some true dividing lines when it comes to exercise intensity (like the point at which you can't speak comfortably anymore, or the point at which lactate accumulates faster than you can clear it), but these don't correspond exactly to the typical five-zone system.
The five-zone system, as a refresher, is based on where your heart rate falls as a percentage of your maximum heart rate. There will be specific percentages defined as the boundaries of each zone, and the five zones are usually described something like this:
zone 1: rest or minimal effort
zone 2: easy breezy conversational pace
zone 3: ??? (this is sometimes described as a "gray zone" you should avoid—I disagree!)
zone 4: pretty hard
zone 5: maximal effort
It's a cute idea, and many people find this system helpful, but these zones are not based on any scientific findings that prove we get such-and-such benefits at 60-70% of max heart rate, and such-and-such different benefits at 71-80%. If you aren’t convinced, just look at how different gadgets and apps define the zones differently: Your “zone 2” might be 60-70% on Apple Watch, but 65%-75% on a Peloton. At, say, 73%, the Apple Watch would say you're in zone 3 but the Peloton would say you're in zone 2. Who is right? Neither, really.
Research on the benefits of exercise doesn’t use heart rate zones, or at least not of this type. They may measure intensity in a few different ways, including whether you are above or below your ventilatory threshold (basically, whether or not you can talk while exercising) or your lactate threshold (measured through blood chemistry, but basically the highest effort you can sustain for a long time). Sometimes they’ll measure METs, which relate to how much energy you use to do work, or they'll put everything in terms of oxygen consumption (this is where the term VO2max comes from). Occasionally these studies will send participants home with heart rate-based guidelines, but those tend to be drawn from their personal scientific measurements, rather than the cookie-cutter zones you get from an app or from watching a video on youtube.
Conversational pace includes zone 2 and most of zone 3
Let’s take a closer look at that idea of the “talk test” or “conversational pace.” The guideline to keep your easy cardio at a chatty pace does come from a scientific concept: the ventilatory threshold.
Imagine you start out at a walk, and every minute or so you increase your speed a bit. As you work harder, you’ll hit a point where your breath becomes a little ragged, and your sentences choppy. If you were conversing with a friend, you'd be grunting out a few words at a time, rather than casually telling a story. That point is your ventilatory threshold, or VT (sometimes called VT1).
When athletes or coaches talk about easy pace or easy efforts, they usually want you below your VT. The way people talk about zone 2, you’d think that the VT occurs at the top of zone 2. But nope—conversational pace is closer to 80%, which is the top of zone 3. For example, here’s a study on recreational runners that found VT1 to be, on average, at 78% of the runners’ max heart rate. And they tested the runners’ max heart rate, rather than using a formula based on age. (Never trust the default formulas.)
So if you’re trying to train at an easy pace, or if you’re using the 80/20 rule to keep 80% of your runs easy, you can do those easy runs or cardio sessions in zones 2 and 3, not just zone 3.
Zone 3 is still aerobic and still easy
Now that I've explained why the zone 2/zone 3 distinction is arbitrary, you see why it makes more sense to look at zones 2 and 3 (or even zones 1 through 3) as a continuum. At the lower end, you’ll be running or pedaling slower, burning fewer calories, and feeling like you’re barely doing any work. (Hello, cozy cardio!)
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At the higher end (or the top of zone 3), you’re still getting a lot of aerobic work done, still benefiting your mitochondria and your capillaries and everything else, but you’re doing it in less time. If you’re interested in calorie burn per hour, zone 3 is more efficient.
Cyclists sometimes call training in this range the “sweet spot.” It gives you some of the advantages of harder training without making you too fatigued. For runners, zone 3 may include some of your tempo runs, some of your race-pace runs, and some of your faster “easy” runs.
So what’s the point of zone 2, if you can get all of its benefits in zone 3? That depends on your big picture: If you’re doing a lot of training, you’ll probably want some of it to be in zone 2, if only to save some energy while you’re getting more miles on your feet. But if you only run, say, three times a week, it’s unlikely that those couple of runs will wear you down much even if you do them all in zone 3.
You shouldn’t read too much into your heart rate anyway
This brings me back to my grudge against heart rate monitors. (It’s a grudge borne of love; I track my own heart rate when I run and find it useful in many ways.)
Your heart rate doesn’t only track with your training effort; it also responds to a lot of other factors. For example, it responds to summer heat, showing you higher numbers in hot weather. It can also show higher numbers if you’re more fatigued, or at the end of a run compared to the beginning, and it may show higher numbers if you’re a bit dehydrated. When you run a race, you may find that your heart rate is higher than expected at the start, just because you’re a bit nervous. Some medications can alter your heart rate as well—beta blockers, for example, notoriously lower your heart rate.
And then there’s the question of whether your fitness tracker's zones are set correctly (even knowing that, yes, their boundaries are made up). If you’ve never run an all-out race or series of hill sprints, your watch may have never seen your maximum heart rate. So if it says that your max must be 184 because you are 36 years old, it’s just grabbing numbers from a formula. That makes as much sense as buying shoes based on the average shoe size for a 5’6” woman, rather than actually measuring your feet (or trying on the shoes). If you go out for an easy run and find that your heart rate was in “zone 5” the whole time, I guarantee you that isn’t your zone 5. If you want to be precise, do one of these workouts to test your max heart rate.
So if your heart rate creeps into zone 3 on a “zone 2” training run, that may or may not be accurate. But even if it is, if you can still breathe and speak more or less normally, you’re getting plenty of benefits from your zone 3 cardio.
Is zone 2 or 3 better for fat loss?
Both are good! If you can only do cardio a few times a week, and don't mind working hard, zone 3 is a great place to be. It's less fatiguing than HIIT, but packs more of a punch than zone 2.
But if you have more time, you may want to work toward the 50 to 60 minutes of exercise per day that researchers have found works the best at helping people lose weight and keep it off. (Here's one interesting study where this level of exercise worked even without dietary changes.) This is a lot of exercise! To get that amount of work in, most people would not be comfortable doing it all as zone 3 training—but zone 2 is a lot more doable. The more exercise you do, the more you'll need to include easier work, like zone 2, to give yourself a break from the harder days.
So if you're doing a ton of exercise, at least some of it should be zone 2, and some can be zone 3 or higher if you like. If you're only exercising a few days a week, zone 3 is probably better.
What is the best heart rate zone for cardio?
Every zone has a benefit, so if you're trying to increase your cardio fitness, you should spend time in all of them.
Zone 1 is good for warmups, cooldowns, and the recovery periods between intervals.
Zone 2 is good for long sustained efforts. It's usually OK to do zone 2 in place of a rest day.
Zone 3 helps you adapt to harder work than zone 3. It burns more fat but incurs a little bit more fatigue than zone 2, as we've discussed. It's also the zone where you'll practice race pace if you're training for a race like a half marathon.
Zone 4 helps you to work close to your lactate threshold, which improves your endurance when you're working hard. This is an important zone for athletes, but it's usually only done one or a few times per week, not for every workout.
Zone 5 is a very hard zone, and is great for HIIT workouts (with zone 1 work, like walking, to recover in between those hard intervals).
In general, you'll want to spend more time in the lower zones, and sprinkle in the higher zones for variety. In the 80/20 style of running, 80% of your workout time should be spent in zone 2 and low zone 3; everything from high zone 3 on up should only make up 20% of your workout time each week. This isn't the only way to structure your training, but it's a popular one that helps runners get a good balance of work in all the zones.
Is zone 3 a "gray zone" with no benefits?
Not at all! It got this reputation from all the coaches and writers who were trying to convince people that training medium-hard shouldn't make up all their training time. Instead, they should do some sessions easier (zone 2), and some harder (zone 4 for threshold and zone 5 for shorter and harder intervals). The idea of emphasizing the highest and lowest zones is sometimes called "polarized training." But this advice somehow turned into a myth about people needing to avoid zone 3, which was never true.