When & how to lift heavier

Experts explain the science of progressive overload and how to safely build strength without risking injury

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Many of us go to the gym to bulk up. But how does it actually work?

When you lift weights, it increases tension on the fibres in your muscles, and causes metabolic byproducts (such as lactate and hydrogen) and inflammation to build up in the muscle tissue. These signals tell your muscles to adapt and grow stronger.

But if your aim is to build muscle, lifting the same weight the same number of times every week won't be enough; you need to continually increase the load or do more repetitions. This is known as “progressive overload”.

So, how do you know when to increase weight? And how much should you add? Let's take a look.

Knowing the ‘how much’

No matter how keen you are, the exact rate your muscles develop is mostly outside your control.

Your genetics likely play a role. Some people will simply adapt to lifting weights faster than others, meaning they can add weight more quickly. However, lifestyle factors are also important.

Your body is more likely to be able to adapt when you get enough sleep, eat enough protein and keep life stress to a minimum. Otherwise, your progress is likely to be slower.

If you're new to weight training, you will also likely improve faster than someone who has been training for years. This is sometimes known as “newbie gains” - especially noticeable in the first year of training.