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Strength training 101: Is it better to lift heavier weights or do more reps?

Both types of weight lifting burn fat and aid weight loss. It all comes down to the type of physique you're after.
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As a personal trainer and weight-loss coach, I am constantly answering health and fitness questions from my clients, on social media and in our Start TODAY Facebook group. In this column, I address some of the most common questions and roadblocks that trip people up on their journey to establish a health and fitness routine. 

There is so much conflicting advice on how to approach strength training. On the one hand, every gym has giant dumbbells that seem like the domain of the ultra-fit, so it's tempting to assume that heavier equals better. On the other hand, some strength training regimens don't even use weights. If they do, they're small, but it seems like you have to do a million reps to get that lithe, lean look.

This leads a lot of people to wonder which approach is right for them. Let's break it down.

Is it better to lift heavier weights for fewer reps or lift lighter weights and do more reps?

Many fitness professionals reason that less reps with heavy weights build your muscle mass, while more reps with light weight increases your muscle endurance. So, which is more important?

Confusingly, the answer is both.

When you lift heavier, lower repetitions are advised for the obvious reason: it is harder to lift heavier weights and your muscles fatigue faster. But what this also means is that your muscle size will increase more and faster the heavier you lift.

On the other hand, lifting lighter weights for more repetitions will improve your endurance and build muscle, but not as quickly as lifting heavier weights. It truly depends on what your goals are for your physique. If your goal is weight loss, both lifting heavier and lifting lighter can help you burn fat and lose weight.

In fact, one study showed that after 8 weeks of strength training, those who lifted heavier weights with less reps had more strength. But the study also showed that people who lifted with lower weights, but high reps, had more muscle-building activity.  

Determine your fitness goals and your mindset

As a weight loss coach and personal trainer who specializes in women’s health, most of my clients want a sleek and toned look. That look is usually achieved — no matter what your current size or weight-loss goals — by doing more repetitions with lighter weights.

And, there's also an argument to made that if you're already stressed out by trying to lose weight, your body doesn't need the added stress of lifting heavy weights. When the body is exerting itself at maximum capacity and stressed out in order to perform a few repetitions at a heavy weight, sometimes this can be counterproductive.

Many of my clients come to me stressed out or fatigued. The last thing their body needs in order to lose weight and get the physique that they want to achieve is more stress on their body. Therefore, exercising at a consistent and steady state with lower weights and higher repetitions gives them the results they’re after.

On the flip side, if you are someone who doesn't feel stressed out by fitness and loves a challenge, heavier weights may be a good choice for you. Even if weight loss is your goal, if you don’t feel stressed, then exercising with heavier weights for less repetitions may be perfect for you at this stage in your fitness journey.

I always advise my clients to try a workout program consistently for three weeks. If you don’t see results after 21 days, then it’s time to try something new. So give lifting heavier weights with less repetitions a try if you feel like that’s best for your body right now. If you lift heavier weights, you’ll likely notice that your strength increases faster — which may be your goal!

How do I know when it is time to increase my weight or reps?

The next question my clients ask is how to know when it’s time to increase weight. We all want to feel like we’re making progress in our fitness routines. When it comes to strength training, does that mean you need to increase weights, reps or both?

If you’re someone, like me, who bulks up easily — and doesn't want to — then the answer is to stick to lower weights with higher reps. I do not lift weights heavier than 7 pounds because when I do, my shoulders, back and chest bulk up in a way that I don’t like. I like to maintain a sleek and toned look, so I prefer to stick to my 3- or 5-pound dumbbells. If my body feels bored or the workout is too easy, then I change it up using resistance bands or doing bodyweight exercises — like lots of planks! Instead of increasing the weight, I just change up the exercises altogether.

But if you’re just starting out with strength training, you can focus on a progression. Try this: Start with 8 repetitions of an exercise using 3-pound weights. Perform three rounds of all of the exercises in the circuit. Then, after doing this every other day for 2-3 weeks, increase your repetitions to 10. Repeat for 2-3 weeks. Then increase the repetitions to 12, and finally up to 15. Once you’re performing 3 rounds of 15 reps for 2-3 weeks, increase the weight to 4- or 5-pound dumbbells, and then repeat the whole cycle.

If this is too easy and you feel like the progress is too slow, then speed it up! But try to focus on your overall strength and progress instead of increasing your weights. It all comes down to how you want to look and feel in your body.

More of your questions, answered!