High Intensity vs Low Intensity Workouts - Let's See What Works

In the 1960s, a smart chap called Kenneth H Cooper (a doctor of medicine and former Air Force Colonel from Oklahoma) came up with the concept of aerobics. Yes, like you, I thought this had been around from the beginning of time, but, no, someone did invent it.

Originally the aerobics system was based on a points system that measured different activities like running, walking, swimming, tennis, basketball, etc which was a way of improving cardiovascular health which is commonly known today as “cardio.”

Even though the idea was based on helping people improve their cardiovascular system, it very quickly became a way to help lose weight and burn fat quickly.

This makes sense because the type of exercises this covers do indeed help you lose weight when combined with a healthy diet. It burns calories which then helps you burn fat. This helps activate the “Aerobic Energy Pathway” in the body. 

This energy system is quite a clever way of using stored fat in the body after being converted into fatty acids, combined with oxygen and other chemicals to produce the body's sole source of energy called adenosine triphosphate. Let's call it “ATP” for short. As long as this pathway is utilised, more and more fat will be burned over time.

Low-Intensity Training

Earlier studies concluded that exercising over a longer duration and with low intensity like running, jogging or cycling led to a series of other low-intensity exercises we have today like aerobic dance classes, yoga, step aerobics and the ever-popular Zumba dancing.

Even though these low-intensity exercises are still the most popular forms of exercise that people perform today. Newcomers have arrived in different shapes and forms to battle for the exercise crown.

One of the most unpopular reasons why low-intensity exercises are starting to decline is the duration and time it takes to do these exercises.

These days, people just don’t have the time in their busy lives to incorporate an hour-long session anymore.

If you are just getting started, then low-intensity exercises are fun at the beginning. However, after time people start to get fed up with it. It starts feeling really competitive and taking up way to much of their time.

It stands to reason that the more people that get bored or lose interest, the more people will quit and look for an alternative.

Is there anything better out there?

Let me introduce....

High-Intensity Interval Training

The exercise isn’t really that different from the header. It involves any exercise that is of high intensity and is broken up into several intervals. 

This is commonly known today as HIIT training. The concept is high-intensity periods of training followed by intervals of low periods of recovery.

Now, the most popular exercise at the moment is a combination of sprinting and then walking. 

The sprint interval generally lasts between 5 and 30 seconds and each walk interval we also last between 5 and 30 seconds. 

The fitter you are, the higher the run to walk ratio is (you will run for longer and rest for less). The opposite applies to those that are less fit who would rest for more time than they ran.

The total session length varies between 5 and 20 minutes and because it is such an intense workout, they recommend that you should only do this about three times a week. When you add those sessions together, that only amounts to just 60 minutes of exercise a week.

“Not bad”, I hear you say.

You’re probably wondering what the science is behind this? I know I was when I first heard of HIIT training.

When your body goes through intense activity like this, it needs to be able to keep up with the energy demand your body is shouting out for.

One of the best ways to do this is by secreting high levels of fat releasing hormones known as catecholamines (I also had never heard this term before) into the bloodstream. With the increased demand of these hormones into the blood system, the faster you will burn calories and fat. The fatty acids are used to replenish your energy stores.

Studies have also shown that with increased HIIT type exercises you create in turn create a strong EPOC effect, which is short for “Excess Post-exercise Oxygen Consumption”.

This is basically the extra oxygen your body needs to after intense activity. The more oxygen you take in, the more calories you will burn. Believe it or not, this effect can last for a staggering 24 hours after a workout.

Note: There studies that suggest the number of calories burned during this period is a lot less. That’s why it always best to combine intensive exercise with a healthy diet too.

So, we have talked about all of the good things with HIIT. What are the drawbacks?

Firstly, taking part in any HIIT type training is quite hard on your body.

Here’s an extract from What Are The Positives and Negatives of HIIT Training

Let’s face it. HIIT training isn’t for everyone. To be clear, these workouts are hard to do, will burn and hurt every time you do them.

Sure, you can relax and take it easy after the workout. However, during the HIIT exercises, you are likely going to be in a lot of pain. For this reason, it’s not for everyone.

If you are not used to working out this way, then you will likely find this really tough to make the switch. Because of the pain and the burn you could also argue that HIIT exercises aren’t that enjoyable.

For a lot of people, exercising is fun and something they look forward to each day.

If you are going through this amount of pain on a regular basis, you won’t really enjoy it. Hence the reason why this is not for everyone.

Can Cause Dizziness

One of the things that people don’t realise when they are starting out with HIIT exercises is the quick succession of the many different exercises. In a lot of cases, you will be alternating between standing and sitting positions.

Don’t forget that your blood pressure will also increase and drop in quick succession too.

For a lot of people, this may cause them to become dizzy. If you find that this happens during or after your workout. You would be well advised to take a break and chill out for a while.

Can leave Your Muscles Feeling Sore

Even though the exercises are short and brief it doesn’t mean you won’t get sore.

With high intensity comes the higher risk of damaging your muscles on a regular basis. 

Some have described this as delayed onset muscle soreness (DOMS).

DOMS is basically your body responding to such an intense workout. The fact that you are activating and working for so many muscle groups over a short period of time increases DOMS dramatically.

Higher Chance of Injury

We have talked about intensity a lot in this article, but one of the things we haven’t mentioned that much is the speed of the exercises.

Since you are doing these exercises a lot faster than you normally would it means you won’t have as much control over your body movements as you would be doing the exercises slowly.

For that reason, your chance of injury is a lot higher than if you doing “normal exercises.” Of course, as you become more experienced and more comfortable the chances of injury should fall. However, if you are just starting out on your HIIT journey, then take care to control your movements as much as you can.

In Summary

The number of people dropping out of low-intensity cardio is rising. But, the same can also be said for high intensity too. Not only will you constantly feel tired, but it is also very hard to maintain each week.

Depending on how strong your joints and muscles are, HIIT training can put a lot of pressure and strain on them and may result in injuries and soreness.

Low-intensity cardio can be done daily and with a little effort where HIIT requires a certain amount of recovery time which can sometimes interfere with other exercises you wanted to do that week. 

So which one is the winner? In a word. None. It all depends on you and what suits your body, your time, and also the recovery time needed. This will vary from person to person, and it may vary depending on your mood or how busy you are on any given week.