Differences between low intensity and high intensity cardios [closed]

Question

What is the differences between a low intensity and a high intensity cardio session?

• Pros
• Cons
• What are they meant for(fat burning? resistance?)

Answer 1

The differences between a low-intensity cardio session and a high-intensity cardio-session are fairly minimal for the average person. A low-intensity cardio session would be something like walking, whereas a high-intensity cardio session would be something like running.

When you work out, and any-time really, your body burns fat and carbs to provide you with energy. Your body might be providing them both in a 50-50 ratio while you're reading this; however, if you were to start running, your body would need to give you more energy. Carbohydrates are the body's main energy source, so your body would start burning more to provide the energy to keep up the high-intensity workout; however, if you were to simply walk, your body wouldn't need as much energy so it could continue to get its energy from fats as well as carbs.

As such, a high-intensity workout would burn less fat per calorie than a low-intensity workout, but for the same duration you'd burn more calories and so it's likely to work out better.

BodyBuilding.com says this:

Say you burn 200 calories doing low intensity cardio and 90% of those calories came from fat. That means you burned 180 calories from fat and 20 from other sources. If you would have done high intensity cardio during that period, you might have burned 300 calories and 75% of those calories were burned from fat. That means you burned 225 calories from fat and 75 calories from other sources.

Both forms of exercise burn fat, and the average person would benefit more from a high-intensity workout, but if you're prevented from doing so don't feel a low-intensity workout can't give you results.

Cross-Training For Dummies* has this to say:

Working out at higher intensities may cause you to burn a lower percentage of fat, but since you burn more total calories, you still use more fat calories.
Low- to moderate-intensity exercise can burn a significant number of calories over a period of time. If you aren't fit enough to push yourself to work at a high intensity, or you have a physical weakness that prevents you from doing so, you can still burn a lot of calories by doing low-intensity workouts for a longer period of time.

High-intensity workout:

If time is a factor; or you don't mind pushing yourself: a high-intensity workout is better.

Pros

• Burns more calories in less time

Cons

• Requires a certain level of fitness first
• Can be tricky if your mind isn't strong enough to keep pushing you
• Injuries or medical conditions can hinder one's ability to do it

Low-intensity workout:

If time isn't a factor; you aren't fit yet; or you don't wish to push yourself: a low-intensity workout would be better.

Pros

• Burns more fat as calories
• Is easier to do for everybody

Cons

• Takes more time to burn the same amount of fat

In summary

Both forms of exercise are for burning fat and getting fit. On average, a high-intensity workout will give better results for the time spent because you will burn more calories. A low-intensity workout may burn more fat as calories, but because your body turns fat into carbs when it needs fuel you're still going to burn through the fat.

* While I can't attest for this particular book from these authors being a reliable source of information, my experience with the For Dummies books is that the authors all have excellent knowledge and experience in the domain they are writing about.