A common joke is that you can simply “lift weights faster” to get your cardio in. High-rep lifting is used in circuit training and in programs like CrossFit to supposedly gain both the benefits of lifting and the benefits of cardio, without needing to go for a run.
However, there are significant problems with high-rep lifting that make it hard to progress, hard to manage, and hard to combine with other exercises in a weekly training program.
Recent research also suggests that high-rep lifting, while it can provide strong cardiovascular effects, provides no additional strength benefits compared to traditional cardio, while potentially producing inferior cardiovascular adaptations.
While I like high-rep cardio sometimes for variety or for working around programming constraints with specific clients, I generally think it’s a case of half-assing your programming when you could just do your traditional cardio instead.
“What do you do for cardio?” asks the foolish virgin cardio exerciser,
“I lift weights faster,” sneers the hulking chad powerlifter.
He lifts weights so fast that he runs a marathon and wins. Soon, everyone is cheering. He’s proved once and for all that cardio is useless. Science is thrown out. All you have to do is want it hard enough.
You can probably guess by now that the above sentences were written with about as much sarcasm as I can muster. But in some ways, it’s pretty accurate about how people think that cardio will work.
“Lift weights faster” is a common recommendation for cardiovascular activity. Many lifters hate doing cardio, and would rather do more lifting, faster, if they can get away with it. And sometimes, for these people, that can be enough. It all depends on your goals.
However, I would argue that while it’s doable, it’s probably not optimal. Before the “lift weights faster” crowd decides to get out the pitchforks, I’m not saying that you can’t get your cardiovascular activity in that way - you absolutely can, and if you hate other kinds of cardio so much that you’d rather do it, then all power to you. For a baseline level of cardiovascular activity, enough to keep you lifting heavy weights, yeah, lifting weights faster may be enough.
That being said, there are a few reasons why “lifting weights faster” is never an approach I’ve used as a first option. I’ve absolutely used it - with clients who hated cardio, clients who didn’t need optimal cardiovascular training, or clients who don’t have a ton of time and enjoy high intensity activity. Still, when they can stomach it, I usually prescribe clients more traditional cardio.
The reason has a lot to do with the way that cardiovascular activities and lifting activities are fundamentally different kinds of exercise.
In most lifts, there are very typical cycles of movement. When you bench press, for example, you initiate with a lowering (eccentric) phase, there’s some period where the bar is neither raising or lowering (isometric) (even if that’s very short in a touch and go bench press) and then you’re pushing it from the chest to lockout (concentric), followed by another pause in which you’re neither raising nor lowering (isometric).
This cycle can be different depending on the lift in question. In some lifts, you start with the raising (concentric) portion of the lift, and then the lowering (eccentric) portion follows. In some lifts, there’s only concentric phases, and then weight is either dropped or falls of its own accord without an eccentric phase. No two lifts are exactly the same.
But virtually all lifts follow this fundamental sort of cadence - back and forth, repeatedly, with miniature pauses in between.
Cardiovascular activities, on the other hand, are what we call “cyclical” activities, in that effort is typically alternated from one limb to the other. While one leg and foot is being raised, the other is lowering. While one arm is pushing, the other is pulling. While the upper body is moving, the lower body is getting in position to move next.
Unlike lifting, these movements do not have this back and forth, “pausing” sort of motion - instead, motion is fluid and continuous, and goes until you stop, willfully or otherwise.
The reason that cyclical cardiovascular exercises are so good at getting our heart rates up has to do with this continuous motion - when you’re constantly in motion, your heart rate gets a lot higher, and stays that way because there’s no rest, no pause, no downtime. When you’re in constant motion, your heart rate will slowly and steadily increase over time, even if the actual metabolic demand of any individual part of motion is very low.
So the real question here is “can non-cyclical motions mimic cyclical motions in terms of their cardiovascular effect?” and the answer is of course yes, but there are greater limitations.
Because your heart rate spikes and then falls when you complete a heavy set of weights, you do get some cardiovascular effect from lifting those weights. But when the set ends, your heart rate quickly begins to fall back down and normalize - and without something to keep it high the way cardio does, you won’t get much of a consistent stimulus and your body will only weakly adapt to it, cardiovascularly.
One thing you can do is greatly speed things up. By speeding up your reps you can minimize the pause time between reps and thus keep your heart rate more consistently elevated. However, this is a problem for two reasons.
One is that when you’re using a weight light enough to get your speed up pretty high, and keep it that way, that also means that, by definition, you have to be using a pretty light weight. The amount of weight you can put on the bar, and the amount of reps you can perform are inversely related - so if you’re using a weight that you can consistently lift fast for a long time, it has to be so light that it will have minimal impact on the kind of strength and muscular adaptations you need for heavier lifting. In short, there will be little carryover to your strength, although you can still build some size.
The second reason is that there are limits to how fast you can do things. A bench press has to move back and forth - so you’re constantly not just accelerating the bar, but accelerating it against itself - you have to move it in one direction and then very rapidly move it in the opposite direction. Since you have to slow down and reverse the trajectory of the bar, there are limits to how fast you can actually get - and this means that you can’t scale this forever. You may be able to get more cardio from lifting faster, but you can’t lift faster and faster forever - once you hit those limits, you can’t follow the principle of progressive overload to continue to improve.
Another option for lifting weights for cardio is to specifically select exercises that are particularly metabolically challenging, to get your heart rate up quickly. The staples of CrossFit circuits - deadlifts, Olympic lifts, jumps, pushups, pullups, burpees, and other compound exercises are all capable of getting your heart rate up pretty rapidly just because they use a lot of muscle at once, and therefore also burn more calories, require more oxygen, and tire you out more quickly.
However, while this does “work” it also means that you can’t really take it easy. You can’t ease into it. You can’t scale things down easily the way that you can go for a light jog instead of a faster run. You either do the exercises or you don’t. This leads to a kind of “stickiness” or granularity in planning workouts like this - they’re either hard or easy, and it can be difficult to appropriately adjust the dosage without significantly changing the exercises or number of repetitions involved. This also creates problems in figuring out how to adjust or progress your workouts over time.
Some of these exercises are also high impact. Jumps, burpees, and other plyometric exercises are known for their metabolic challenge. However, this is also a curse because these exercises are scaled to the bodyweight of the exerciser - a 250lb guy jumping is both going to have a much harder time getting off the ground, and will generate more impact forces on landing - potentially risking injury if his tendons aren’t ready for this level of activity. I’ve seen lots of beginners completely wreck their ankles and knees with high volumes of jumps in “beginner” circuit classes, even when they tried to modify things to be more appropriately difficult.
By definition, this kind of cardio has to be high intensity - and high intensity isn’t for everyone. Many people have heard of the infamous tabata protocol, in which exercisers training with just a few high intensity intervals on a cycle got better results than exercisers performing a much longer amount of steady state cardio.
What they often overlook is that this intensity was also so high that it was considered much more psychologically difficult, and that many people would realistically struggle to keep up with a more challenging program like that. The same rule applies to high intensity intervals of weight training for speed - it’s going to be more psychologically difficult, and that’s just not for everyone. I myself have given up on HIIT many times because it so exhausted me, both physically and mentally, that it made it hard to keep up my normal training schedule, even when I was regularly deadlifting twice my bodyweight and doing other cardio workouts with no concerns.
High intensity, while it can make up for a lot, is a tool that needs to be used carefully. You can get better results, but you can also far more easily burn out, get yourself hurt, or just throw off the rest of your life entirely.
This analysis of lifting weights faster is supported by recent research. A study of lifting weights faster found that lifters adopting a high-rep cardio program gained no additional strength compared to traditional cardio, and saw lower predicted aerobic improvements. An analysis of this study by Greg Nuckols in MASS also suggests that the high-rep program was also more exhausting, more likely to throw off recovery elsewhere in the program, and more likely to be hard to work around. In short, just doing your cardio seems like a far more flexible approach.
A the end of the day, you can lift weights faster to get your cardio in, but I think you’d get a far better return on your effort if you just decided to… go for a run here and there. If you can get similar results for less effort, why not do that? Why not focus on something that’s more efficient for your time spent? And hell, if you’re still big on high intensity stuff, you can do sprints or bike sprints.
Lifting weights faster can work, but to me it’s a classic case of half-assing two things instead of whole-assing one thing. Don’t waste your time with half measures, just stick with the stuff that works best.
I’ve been writing a lot about cardio lately. Here’s a few recent posts on the topic that may interest you:
About Adam Fisher
Adam is an experienced fitness coach and blogger who's been blogging for 5+ years, coaching for 6+ years, and lifting for 12+ years. He's written for numerous major health publications, including Personal Trainer Development Center, T-Nation, Bodybuilding.com, Fitocracy, and Juggernaut Training Systems.
During that time he has coached hundreds of individuals of all levels of fitness, including competitive powerlifters and older exercisers regaining the strength to walk up a flight of stairs. His own training revolves around powerlifting and bodybuilding.
Adam writes about fitness, health, science, philosophy, personal finance, self-improvement, productivity, the good life, and everything else that interests him. When he's not writing or lifting, he's usually hanging out with his cat or feeding his video game addiction.
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