Intensity and post-workout effects are the keys to burning body fat. Forget about long, gruelling cardio routines that last for an hour or more. Forget about spending 45 minutes on the treadmill – what a waste of time that is. Forget about going for a ‘jog’ for an hour – do you seriously want to damage your joints? How many ‘joggers’ do you see out on the road who look like they are in real pain? I see many of them.
To burn fat, all you need is a minimum of 12 minutes and no more than 20-30 minutes per workout performing short intense exertion periods. In running terms, you would do sprint intervals rather than go jogging. Of course, sprinting would be to your current level of fitness. How many sprinters do you see who look muscular, fit, strong and most importantly, healthy? The answer – ALL of them!
The trick is to trigger an ‘after burn’. This happens when your body burns fat after you stop exercising. It’s all about what you use for energy during exercise. During the first minute or two, your body burns ATP for energy (don’t worry too much about the jargon here). This is your body’s most potent and available source of energy. It’s used for quick bursts of movement but it doesn’t last long (like sprinters).
After a few minutes, your body shifts gears and starts to burn glycogen (stored carbohydrates) in your muscle tissue. This lasts for 15-20 minutes. When you stop exercising during this process, your body will automatically burn fat to replace the carbohydrates you just burned. This ‘after burn’ melts away your stored body fat.
You’ll continue to burn fat up to a full day after you finish each session. This is largely due to the boost your metabolism gets from your training. Because your body needs extra calories to repair muscles, replenish energy stores and restore your body to homeostasis, you continue to burn calories (and fat) long after your workout is over.
After a few months, your body stops storing fat because it simply doesn’t need it. This is the opposite of conventional advice, which tells you to burn fat during exercise. But this only makes matters worse. This tells your body to make and store more fat so you’ll have something to burn during the next workout. This is why so many people get frustrated when they don’t see results after months of spending hours in the gym.
Turning up the intensity after each interval and keeping your workouts short will take the fat off.
Take a look at these 2 examples:
Session 1: You do 20 minutes on the exercise bike at continuous pace with no rest. Your heart rate is a constant 60% of your maximum heart rate.
Session 2: You do 20 minutes on the exercise bike in numerous short bursts of 15-45 seconds while resting (recovering) in between. Your heart rate fluctuates between 60% and 80% of your maximum heart rate.
What happens in each session?
Session 1: You burn a total of 150 calories. 60% of those calories would come from fats and 40% from glycogen. This means you burned 90 calories from fats and 60 calories from glycogen.
Session 2: You burn a total of 250 calories as the demand is much greater. This time only 40% of those calories would come from fats and 60% from glycogen. This means you burned 100 calories from fats and 150 calories from glycogen.
What does this mean?
In the same amount of time, i.e. 20 minutes, you burned 100 more calories in session 2 plus more calories from fats even though the percentage using fats decreased. Session 2 also depleted your muscle glycogen, meaning you need to replenish your glycogen stores and repair muscles after your workout. What do we use as energy to do this? Fats! So with session 2, you get the ‘after burn’ effect up to 24-48 hours after your workout.
Also, consider these further benefits of using short-duration intervals:
- Your heart becomes stronger and more efficient so can handle stressful situations much better
- Your heart can pump more blood per beat when maximally challenged
- Reduces the ‘bad’ cholesterol and increases the ‘good’ cholesterol
- Provides an anti-ageing benefit by raising testosterone levels, which fights against memory loss, accumulation of fat, low libido, sexual dysfunction and loss of strength and bone.
If you want to know how to change your training or how to start on a fat-busting journey, contact me on 07990 583034, email pauledgar@bodyandmindfitnesscompany.co.uk or visit www.bodyandmindfitnesscompany.co.uk
Paul Edgar
Personal Trainer