In my opinion, this is arguably one of the most misunderstood and misused words in fitness. 

It sounds simple, right? If you Google the definition, the internet is bang on:

“the measurable amount of a property, such as force, brightness, or a magnetic field”

So where is the confusion? And why is it important?  

Intensity is a measure of output. On a bike, it is wattage, in running it is speed or cadence, for weight lifting, it is the load on the bar, for power work, it is velocity. (Note: heart rate is not a direct measure of intensity). 

But, how hard you think you work is not intensity. Putting four exercises together with little to no rest, yeah, it makes it harder, but depending on the exercises you selected, it’s pretty much guaranteed the intensity was lower. What makes it hard is the density of the session, lots of exercises back to back or the total volume of work completed in a time frame.

Why I think it’s important to know this is so you can better understand what you are trying to achieve in your training. Suppose you do repeated bouts of intervals and don’t rest adequately to recover from the first bout. Each bout thereafter will be slower, so you’ve gradually lowered the intensity as you train. 

Yes, this might be brutal, but the intensity drops each time you go slower. So tweaking the rest to match your ability to recover is vital.

 If you do weight training and reduce the rest periods or superset multiple exercises and you can’t manage as much weight, you have made the session higher density and lowered the intensity. Even though it feels harder, it’s not higher intensity. And, if you are weight lifting for strength and hypertrophy, that’s not what you want.

I see many people tweak their sessions to make them “harder” in the belief that harder = higher intensity and higher intensity is better. 

High intensity has its place. See my ‘Master the Basics’ blog on HIIT here. Just make sure the changes you make are actually doing what you want. Also, know that you want a range of intensities across your training. In some situations, moderate-intensity sessions are just as good if not better than high-intensity sessions.

Stay tuned next week for another instalment of Master the Basics and don’t forget to follow me on Instagram where I share exercise techniques, and show you how to maximise your training. I hope you enjoyed this blog post, if you have any questions I host a weekly Sunday Q&A session on my Instagram channel. Otherwise, please feel free to email me at andy@andyvincentpt.com. 

If you want to get in touch and see how I can help your fitness and become your Online Personal Trainer, click here.