Have you ever worked out so hard you pee a little? These days, it's all about intensity and the 'go hard or go home' mantra, but when it comes to risking injury, it's okay to drop the weights.

How to avoid overdoing it at the gym - Women's Health and Fitness

Reputation vs reality

Don't fall victim to looking at your fitness with a 'more now equals more later' view. If you train at high intensities for a long period of time, you're more likely to risk injury and over do it.

"When we train, we should consider not only the optimal dose of exercise that will result in the greatest benefit but also the potential risks associated with an increased amount of exercise," says Lim.

The importance of recovery

Balance and recovery is vital for both HIIT and heavy weight training because they use the same energy system: the anaerobic energy system. According to Ryan Andrews of Precision Nutrition, "most high-intensity physical activity is a state of 'crisis' in the body: it endangers oxygen supply to tissues, increases body temperature, reduces body fluids and fuel stores, and causes tissue damage." These sessions are very demanding so recovery is important.

But what does intensity really mean?

Think cardio – running, HIIT, etc – intensity is measured as a percentage of your maximum heart rate (MHR), which you can calculate using the basic equation 208 – (0.7 x age).

Cardio

This means working at around 90 per cent of MHR or higher, according to exercise physiologist Yujin Lim from Optimal Health Exercise Physiology in Melbourne.

Here's the break down:

High intensity: > 90 per cent MHR – can't sustain for more than 10 minutes

Vigorous intensity:70 to 90 per cent MHR – can't sustain for more than 30 minutes

Moderate intensity: 50 to 70 per cent MHR – can sustain for 60 minutes

Strength

It's not always getting your heart pounding and sweat flowing when it comes to strength training but more so for muscle growth. Intensity is usually measured as percentage of your one-rep max (percentage of 1RM), or the amount of weight you can lift for a single rep before fatiguing.

Here's the break down:

Intensity for strength: 80 per cent 1RM (one – can sustain for three to six reps

Intensity for hypertrophy: 60 to 90 per cent 1RM – can sustain for eight to 11, and three to five reps respectively

Intensity for endurance: < 60 per cent 1RM – can sustain for up to 20 to 28 reps

NEXT: How to set the correct fitness goal.