The Ultimate Guide To Cardio

Cardio seems to have fallen out of favour these days, but that doesn’t stop it from being a powerful tool to help you achieve better health and a more defined body.

In this post I’ll tell you why you should definitely be doing some cardio, which types are best for you, and I’ll cover some of the more common cardio-related questions that I hear often as a personal trainer.

Why You Should Definitely Do Cardio

Cardio has a ton of benefits for anyone who wants to look, feel and function better. Better cardiovascular health doesn’t just mean you can run for longer, it means you’ll think more clearly, perform better in other exercise, recover better from all exercise, feel better, and generally be less likely to die.

Cardio is good for you. Given that heart disease cover over one fifth of all premature deaths in the UK, and that cancer covers over two fifths, with a significant portion of those being associated with obesity, there’s really no good argument against keeping your heart healthy and your weight down.

Cardiovascular exercise is like biceps curls for your heart, people bang on about those who skip leg day but then don’t do cardio. Train your whole damn body!

Cardio Benefits

  • Burns more calories
  • Burns more fat
  • Improves cardiovascular health
  • Improves mental health
  • Improves cognitive function
  • May promote growth in some regions of the brain
  • Improves work capacity for other exercise

How Do I Do Cardio?

Cardio is anything that challenges your heart and lungs. It doesn’t have to be a specific movement or exercise and it doesn’t need a piece of expensive equipment, you don’t even need a gym membership if you don’t want one.  You simply move vigorously enough to challenge your heart and lungs. That’s it.

Make sure you pic a form of cardio that you enjoy, or at least don’t hate. If you have bad knees then choose something lower impact instead of running.

What’s The Best Way To Do Cardio?

The best method is the one you stick to. With that said, lets look at a few popular types of cardio.


LSD, in this instance at least, stands for Long Slow Distance, and LISS stands for Low Intensity Steady State. They’re basically the same thing, a low-intensity effort sustained for a fairly long period of time.

While not the most time-effective way to do you cardio, it is the best place for most people to start. It isn’t too hard to recover from and it’s easy enough that you don’t dread your cardio workouts. You improve your fitness not through the intensity of exercise but by enhancing your endurance to sustain the exercise for longer.

In terms of calories burned, it’s pretty effective. You couldn’t sustain the exercise half as long if you doubled the intensity so there’s a greater potential to burn calories with the slower forms of cardio, obviously the actual amount of calories burned depends on how long you sustain the effort and how much time you put in.


HIIT stands for High-Intensity Interval Training. High Intensity Interval Training is efficient but not always ideal for beginners. Often you’ll hear all about the ‘afterburn effect’ which makes this form of cardio vastly superior to lower intensity training, but unfortunately you must have a genuinely intense session to get a meaningful elevation in metabolic rate after your training sessions. Most people would be better off training a bit longer instead.

I think misinterpretation of Tabata’s work has glorified HIIT and made it appear to be something that it isn’t. When done right, it is very effective for improving anaerobic and aerobic fitness simultaneously, but it isn’t going to get you ripped.

Intervals mix things up and keep your cardio from getting too boring, so I would advise adding at least some intervals into your training to keep it interesting.


More than just a funny sounding word, Fartlek is Swedish for ‘speedplay’. It is a blend of steady state and interval training done within a longer duration effort. While it is unstructured by its nature, it burns calories, improves fitness and is only as boring as you make it.

The Secret To Enjoying Cardio

Cardio can seem a bit mundane to many but everyone knows a runner who just loves it. The difference is in the mentality. If you’re on a treadmill just watching the clock then of course you’re going to get bored. If you’re challenging yourself and aiming to beat your past time, or go further than you did last time then you’re going to be more engaged with what you’re doing.

Set yourself little targets or milestones and you’ll enjoy cardio a lot more. Cardio is the most efficient way to burn calories, but it doesn’t just have to be burning calories.

Common Cardio Questions

How often should I do cardio?

Generally, more often is better. I’d suggest twice per week as the minimum. There’s no harm in doing cardio daily, you may just need to vary the exercise every so often to give your joints a break.

Should I do cardio on an empty stomach?

You can do cardio on an empty stomach. This may facilitate better fat loss as your body is already in a fasted state. You won’t lose muscle either…

I hear that cardio will make me lose muscle, is it true?

Nope. Not using your muscles will cause you to lose muscle. Inadequate protein intake, or excessive calorie restriction will cause you to lose muscle. Cardio will not cause you to lose muscle.

Should I do cardio before or after weight training?

You can do a short amount of cardio before weight training sessions to warm yourself up, but you should aim to be mostly fresh for weight training sessions because you’ll be weaker if you’ve already fatigued your muscles. When you lift weights, you release a bunch of hormones that are very conducive to fat burning, but weight training doesn’t burn a huge number of calories. Lift then follow with cardio for the best results.

Does yoga count as cardio?


What should my heart rate be?

Typically it’s recommended that you train at 60-80% of your heart rate. You can put your age into the calculator below to work out what that should be.



That concludes the ultimate guide to cardio!

Until next time,


Theo Whittington


  1. Great advice as always! Cardio with you and the team was the most fun I have ever had whilst doing something I had always hated.

    • It was a lot of fun wasn’t it!
      Maybe some day I’ll bring back the beach bootcamps!
      Maybe when it’s warmer though…

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