The Light vs. Heavy Weights Debate: Which Is Better?

by | Mar 4, 2014 | 19 comments


I am often asked: Should I lift heavy or light weights? Won’t lifting heavy make me bulk up? Isn’t lifting light weight just a waste of time? And while I know many trainers would disagree, my answer is that both types of training can offer significant benefits. You’ve probably heard many experts down play the effect of lightweight training, saying they just aren’t enough to offer any kind of real challenge or stimulus for your muscle (and if you are only doing a few reps here and there with them, never reaching muscular fatigue, I would agree). And on the other end of the spectrum, I’ve heard a few experts suggest that lifting anything over three pounds is a recipe for enormous bulk in women (to be clear, I’m not saying this at all – women DO need to be able to lift heavier loads, and do it quite often just during daily activities alone).


One major thing to consider, is what exactly heavy and light loads mean to your body, at this stage of your fitness journey. If you are just starting out with strength training, or returning from a long hiatus, what some may consider ‘lighter’ weights may be plenty of resistance to fatigue your muscles while still allowing you to be able to maintain good form, alignment and control over the weight. It may take some time for you to master the exercises with a much lighter amount of weight before it’s appropriate (or safe) for you to increase to the next level. You can also adjust the amount of repetitions (or repeating the number of same exercise you do) to help add more challenge to your muscles without yet adding more weight if your body isn’t quite ready for it. On the other hand, if you have been training for years, at the same weight range, and are no longer seeing positive progress, it may be time to consider up leveling in terms of your load.


The good news is, if you prefer lifting lighter, studies show that when worked to the point of fatigue, lighter weights can be just as effective at building muscle and strength. In fact, one recent study published in the Journal of Applied Physiology found similar benefits when comparing strength training with heavier loads and less reps to lighter loads using more reps. As reported by Science Daily, one of the lead study authors Cam Mitchell, a PhD candidate in the Department of Kinesiology, noted, “we found that loads that were quite heavy and comparatively light were equally effective at inducing muscle growth and promoting strength.” A separate study, published in the journal Applied Physiology, Nutrition, and Metabolism, also found that using lighter weights and higher repetitions was equally effective in stimulating muscle proteins when compared to heavier intensity and lower repetitions. Researchers also note that an “additional benefit of the low-intensity workout is that the higher repetitions required to achieve fatigue will also be beneficial for sustaining the muscle building response for days.”


Personally, I’m a fan of both types of training, but believe that the choice of which you decide to use depends on your body, your personal fitness goals, the workouts, rep and set counts, and tempo you prefer to use (faster paced routines, for example, can increase your risk of injury if you are moving with very heavy loads). While it’s true that you’ll need to use less reps to get the job done with heavier weight loads, you’ll also need to be using excellent form and control as the potential strain or stress it will put on your joints increases with the weight you lift. If, for example, your goal is to put on a significant amount of muscle mass in a short amount of time, lifting light probably isn’t going to be the best or more efficient method for you. On the other hand, if you suffer from joint issues or simply don’t have access to heavier loads (if you train at home, for example) lighter weight training may be a more appropriate fit for you. I think the right program can offer a combination of the two types of training for maximum safety and benefit, but it’s always important to pay attention to how your body feels and responds to your workouts so that you’ll be able to stick with them for the long term (because, as one of my favorite sayings goes, ‘consistency trumps intensity’ every single time). All of the research, experts, advice etc. is great, but the bottom line is that you know your body best, so be sure to focus on what works and feels best to you.


Tell me, what kind of weight do you like to use during your strength training workouts? What are your thoughts on this debate?


Sources: Canadian Science Publishing (NRC Research Press). “Building muscle without heavy weights.” ScienceDaily, 26 Apr. 2012. Web. 13 Jan. 2013. McMaster University. “Light weights are just as good for building muscle, getting stronger, researchers find.” ScienceDaily, 30 Apr. 2012. Web. 13 Jan. 2013.

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  1. Katie

    When I strength train I use 10-15-20 lb weights. For barre, yoga, or quick aerobic workouts I use 2-3-5 lb weights. Mostly I listen to my body. If something feels like it is gonna snap off, instead of pushing and hurting myself I’ll drop down weight wise or alternate arms or pause for a rep or two. Just depends on whats being performed. Cardio is my weakness so give me heavy strength training any day! I think that stems from growing up on a farm. I feel like I am accomplishing something.

  2. pauldanielray

    From a physiological standpoint, it depends what you are working towards, looks, strength, or looks and strength.

    Doing reps of short sets with heavy weights damages the muscle tissue.. this leads to ‘bulking’ as more muscle fibres are produced in the repair process.. but this only adds a small gain for strength (think of a weight being suspended on cotton.. bulking is basically like adding an extra thread of cotton every now and then).
    The perfect example of this is the massive guys that do the weights in the Olympics.. yes, they can lift massive weights.. but they can usually only do it for a short time.

    Whether you have big or small muscles, using light weights for long sets to the point of fatigue actually ‘conditions’ (removes the rubbish and makes the fibres more effective) what muscles you have.

    This is basically contrasting aerobic and anaerobic exercise.. ideally you need to do both.

    An example from my own experience:
    Up until recently, I have always been quite a scrawny looking guy.. but I worked in the cellar of a bar for ten years.. every Christmas we had to order so much beer that it didn’t fit into the building so we had to stack the kegs on top of each other! these hold 22 gallons of beer and weigh about 14 Stone when full.
    every year, the door staff would offer to help me do this (these guys looked like the incredible Hulk next to me!) and most of them couldn’t manage 1, let alone 20 of these beasts, so I had to mostly do it by myself (and then take a very long break!)

    The point of this story, these guys spent all day in the gym, bulked up and had huge muscles.. but no strength. Whereas I spent all day carrying boxes and kegs back and forth for long periods.. I had the strength, but looked like a stick! 🙂

    Now I do both, I use 2.5kg for long (50+) sets every day, and once or twice a week use 10kg for short sets to ‘bulk up’ a little.

  3. Chiara

    I usually use 3 kg weights, because I usually have only those. For the ballet and pilates routines they are really too heavy and sometimes I have to put them down. On the whole, using weights that are a bit heavy for high repetitions has improved my overall strength. I can manage 5 and 6 kg weights when they are required and I can now do pushups on my toes. You always have to push yourself as far as you safely can and you’ll be seeing results. Of course, I have not been gaining bulk, but I’m defined and stronger.

  4. Joni O

    I’ve lifted both heavy and light over the years, mostly switching it up every other week. However, for the past 7 weeks I’ve been lifting heavy 3X/week – just my own routine at home – and I’ve noticed a big difference! I had been really slacking off the weights for quite some time and exercising very inconsistently. My strength has come back very quickly and I’ve been able to double what I’m lifting for most exercises. I’m totally wiped out when I’m done, but it feels soooooo good !!!

  5. charlie

    What an interesting article! It’s true, I often wonder whether the weights I use to train are adapted. I have 3 sorts of it : 1, 2 and 3 kilos. I use those of 2 kilos for triceps and shoulders and those of 3 kilos for biceps. I only take those of 1 kilo when I feel a little tired. I believe that this is not so bad because I find that my muscles are drawn rather nicely without being striking. It is the result I was looking for.

  6. twoone0

    This is the debate I’ve been having so far this year; heavy or light? When I went through the New Rules of Lifting for Women program last year, I did lose inches, but I was often in a lot of pain, probably because I was not using perfect form and also because I was trying to increase the weight I lifted too aggressively. I’m 56 and though I know it’s no excuse for being out of shape, I have to listen to my aging body when it tells me I’m not 20 any more. 🙁

    I’ve started the NROLFW over again and find myself on a guilt trip when I’m not lifting as heavy as I was, but I surely do appreciate not feeling like I was hit by a truck the next day. Slow and steady wins the race, at least that’s what I’ve always heard, right? I just finished the Stride and Strength workout, and I’m sweating, thank you Jessica!

  7. Cheri

    I am currently using much lighter weights than ever, sticking to barre/ballet, pilates, and yoga for weight training. I have to out of necessity as I’m nursing an elbow tendonitis injury. Know what? I am still strong in my daily life. And, I’m more flexible. If I ever wanted to lift heavy again, I think it would have to be after having some PT sessions as I’ve not been successful with that (always re-injuries my old elbow injury). I think either one is great and, as you said, your body’s needs/limitations and personal goals much always be a deciding factor. Thanks for the GREAT article.

  8. hensong

    I love incorporating weights into my workouts. I haven’t been using them for very long and I am cautiously and slowly increasing the weight. I am currently using 3-5 pounds. If the goal is getting to muscle fatigue then I would think that either lighter or heavier weight should work as long as you do the appropriate work. My concern is proper body mechanics when using weights. I’m not sure that I always understand if I am correct and don’t want to risk injury.

  9. Kati

    I work out 5-6 days a week at home with DVD’s & only have a 2,3 & 5 set handy 🙂

  10. Lisa Boshell

    I think this is a great article advocating to simply do what’s best for your own body. I like to do a mix of heavy, light and body weight exercises. I think you can tone your arms very effectively using your own body weight….I mean, have you ever looked at your Yoga instructors’ arms?? Wowee…Yoga arms are very impressive. Jessica, what is your thought about solely using yoga as your method of strength training? I’ve asked this question to many people and most traditional “gym” folks say you have to use weights to be effective. Just curious what your thoughts are.

    • jessicasmithtv

      Hi Lisa! You can definitely get a great workout using just your bodyweight, and enough that you can develop muscle doing it too. In my opinion, I think it truly depends on the type of yoga you are practicing. In some cases, you may not target the body evenly (for instance you may work more of the front of the body and not as much of the back, which can create imbalances). That would be my only reason for not sticking with “just” yoga for strength training.. though I’m not a fan of only doing 1 type of training in general.. I think a balanced routine is your best bet for a healthy, strong and balanced body. Hope that helps!

  11. Mary

    I workout at home and my heaviest hands weights are 20 pounds. I’ve been meaning to get heavier weights since I’m finding with some moves, the 20 pound weights are feeling too light (chest press & dead lift). I do a combination of light and heavy training. It depends on how I feel (I have fibromyalgia and if it’s a day I’m feeling sore, I tend to go lighter weights. I do find this helps with pain, too).

    I tend to try a lift heavier when it comes to my upper body and do less reps. With my lower body, I tend to use lighter weights. For example, if I’m doing lunges with weights, I would use a 5 pound weight in each hand. I find if I use heavier weights when working lower body, it creates more strain on my joints.

    If I’m learning a new exercise, I usually will use lighter weights till I’m sure I’ve got the form down and at that time, switch over to a heavier weight.

    I really enjoyed reading your article, Jessica and I find it so timely since I was wondering earlier this week what would be more beneficial for me. It was certainly very helpful!

  12. Barb S

    I used to lift mostly heavier till I really damaged my joints, especially my elbows going too heavy with palms up biceps curls, using a combination weight and band then followed by some serious snow shoveling. Now it is light weights only, even no weights isometrically, or a slightly heavier weight supported by both hands like a single dumb bell, medball, or kettlebell.. My elbows have been fine as long as I heed their slightest twinge. Just takes one dumb day to chronically damage a joint. Same can be said going too fast with light weights too.

  13. musingsnyc

    Recently, this has become quite the issue in one of my gym classes. Typically, the instructor tells us to start off with a heavy weight (unless we are instructed by her to go with lighter weights) switching to lighter weights if form our form is being compromised. Lately, she has really been drilling in the point for us to use weights higher than 5 when doing back exercises, stating that our back muscles need more weight to fatigue. I tend to agree with her in that regard, but am still on the fence with respect to going to automatically starting off with a higher weight in her class because our reps are usually 15 or 25, oftentimes repeating the set.

    When I feel that my form isn’t compromised, I challenge myself by using a higher weight. I think it depends, as you stated, on the exercise, the amount of reps, and your specific goal. My goal is to have toned looking arms, not lift automobiles 🙂

  14. Susan Phillips

    This is SO timely. I am doing a heavy rotation right now (New Rules of Lifting for Women) and have been pondering whether to continue or change it up to something more endurance-oriented. I always feel like I OUGHT to do heavier stuff; but when I do, I 1) gain weight, 2) dread my workouts, and 3) get very achy. Why in the world I feel guilty for somehow “not doing it right” is beyond me. So silly. I guess “doing it right” comes in different flavors!! I think your post just pushed me over the edge I’ve been teetering indecisively on. I’m going to switch it up.

    • jessicasmithtv

      Hi Susan! So happy you found this helpful! Its funny how we can feel we should be doing things a ‘certain way’ but our body really always does know best! So glad to hear you are giving yourself permission to switch it up and do what feels right for you 🙂 Keep up the great work!!

    • Emily

      Susan, I’m the same way! I love how powerful heavy lifting makes me feel, but I don’t like the increased hunger or the achiness that comes along with it.

      • Susan Phillips

        Emily, so glad you chimed in, good to know I’m not alone! 🙂



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