Whether you are six weeks, six months, or six years into your walking for health journey, you have more energy and you feel better. Raising your walking game has been relatively easy, by doing a little bit more every day you have become accustomed to a more active lifestyle. However, understanding the settings on your treadmill or smartwatch is slightly more difficult. Fat burn Vs cardio is probably the most common cause of confusion, what do these terms really mean in relation to exercise?
Today’s article looks at what both of these phrases mean, what are the benefits of both and how can you use them to your advantage? As an added bonus, and to provide context I have taken a brief look at aerobic and anaerobic energy so you know the truth.
Aerobic Vs Anaerobic Energy
Contrary to some beliefs out there in the stratosphere, you can’t turn fat into muscle and you can burn fat and build muscle at the same time. Both of these misconceptions are likely to be born out of marketing phrases and misunderstandings of well-thought-out routines. The truth is different exercises will require different metabolic processes which can affect the way you achieve results.
Your energy is the result of your metabolism producing adenosine triphosphate (ATP) which simply put, is just the name of the fuel in the state your body actually burns it.
When it comes to the effects of exercise on your body, I have been fascinated for years. However, despite everything I have learned, the word aerobic, still makes me think of women dressed in brightly colored leotards and leggings sporting impressively structured hairstyles. The truth is a bit less colorful, aerobic just refers to the type of exercise that requires oxygen to release the energy stored in your fat cells.
Anaerobic energy, on the other hand, does not require oxygen and your body will utilize your anaerobic metabolism when you overwork your muscles slowly such as resistance training, or at a high level of intensity that your heart rate cannot maintain.
Anaerobic energy can only be produced from carbohydrates and as a result, can only create 3 molecules of fuel (remember ATP) per molecule of glucose. As Aerobic energy burns fat and protein as well, it can create 13 times as many molecules of ATP per glucose molecule. Anaerobic energy burns more calories but cannot be sustained beyond the food you have eaten, and aerobic energy can be maintained for longer periods.
Aerobic energy burns fat directly from your body whereas anaerobic allows your body to use more of the food you have eaten so your body will burn more fat later in the day when your blood sugar regulates.
Fat burn Vs Cardio Relates To Your Heart Rate
Walking further and adding weights to your walk can help you workout slowly to target the anaerobic benefits of exercise without raising your heart rate, however, it is unlikely to be the most optimal way to meet your goals if you are walking for weight loss.
You will achieve most of the magic walking has on offer by speeding up your walk. Most exercise will require both aerobic and anaerobic energy and your body will switch it up as appropriate. As you increase your walking efforts your heart rate will start to increase and your breathing will speedup. Your body is increasing your aerobic metabolism so your heavier breathing is getting more oxygen to the stored fat cells in your body. As you continue to increase your effort your breathing is becoming increasingly labored to the point you cannot physically maintain the energy needed. Your body will increase your Anaerobic metabolism and start using glucose from the food you have eaten.
In the context of exercise, fat burn relates to a level of intensity that raises your heart rate so you breathe more heavily but is sustainable over a long enough period to burn fat. Cardio refers to a higher intensity and will include raising your heart rate beyond your optimal fat burning zone for a sustained period or several times over shorter timeframes, with a full recovery between each set.
What Is Your Maximum Heart Rate
To understand your cardio and your fat burn zones, you first need to understand your maximum heart rate (MHR). You don’t need to be scientific about this as very few people in the world have access to the level of testing you would need to identify your personal max. You just need to do a bit of simple maths (or math if you are North American).
Invariably, the rule of thumb to calculate your maximum heart rate is 220 minus your age. Yes, the experts are saying that when you were born, your heart had the capacity to physically achieve 220 beats per minute (BPM). And then every year you lose 1 beat per minute forever… I’m definitely researching that more but I’ll accept it because all the experts are saying it.
Once you know your MHR, you can start to look at your heart rate zones mine is 185, so let’s take a look.
What Is Your Fat Burn Zone
While the numbers vary, they generally range between 50% and 70% of your maximum heart rate. It should be a level you can maintain over longer periods, I recommend at least 15 minutes but it depends on your level. I like to aim my heart rate between 60% and 70% during my fat burn workouts which is between 111 BPM and 129 BPM
Why Does This Work?
First of all, it is movement and movement requires energy. You will burn calories moving, fast or slow. The more calories you burn, the easier it is to burn excess body fat. Before even factoring in your heart rate, your results are scalable, increased effort will result in increased calorie burn.
When the effort you put into exercises such as walking results in heavier breathing, it is to increase the oxygen levels in your blood. Some of the oxygen will work to break down the glucose in your blood but the idea is the increased oxygen intake is to break down more of the fat cells you have in storage.
This makes sense, as your body regulates your activity, if you do more than your body is used to it has a process to access your reserves. One of the evolutionary purposes for body fat is energy storage.
Reaching Your Fat Burn Zone
Depending on your level you don’t need to get your heart rate exact, as long as your effort results in slightly labored breathing. If treadmill walking is your thing, a lot of equipment will have a Fat Burn setting and will regulate the speed to what it thinks you need. All you do is input a few metrics such as your age and weight and leave the machines to do the rest.
If you don’t trust or have a treadmill, you can consider a smartwatch with a heart rate monitor. I personally love the insights I can get from my Garmin Connect App whilst wearing my Vivoactive 3.
However, I don’t look at my heart rate much while I’m walking. As long as you raise your effort and raise your BPM, you can increase your fat burn rate. You will feel this happen as you start to breathe heavier so you will know you are getting more benefits than just walking at a casual gait. Maintain this speed for a targetted length of time, and if you found it easy to maintain, progress mindset, push a little more next time.
The progress mindset is important as it will help you get the most out of your workout, both now and in the future. As well as scaling up your calorie burn rate, your muscles will get stronger and if you have not increased your food intake you should also lose weight. You will find it much easier to maintain speeds and inclines that previously raised your heart rate more. your efforts will increase and your results will eventually plateau.
Benefits Of Walking In Your Fat Burning Zone.
- As with all walking, there are the usual benefits including aiding digestion, helping to prevent disease, and better mental health.
- Increased effort means more calories will be burned than regular walking
- The calories burned due to your increased effort will be mostly from stored body fat.
Cons Of Walking In Your Fat Burning Zone
- Fewer total calories burned when compared with your cardio zone over equal time periods
- Increased calorie burn rate caused by increased effort is limited to the duration of the workout
- Inconvenient if you have a busy schedule when compared to cardio
What Is Your Cardio Zone
Generally speaking, experts are suggesting your cardio zone is between 75% and 85% of your maximum heart rate. Mine is about 139 to 157. Your cardio zone is achieved when you push yourself so hard that your elevated heart rate is unable to get sufficient oxygen into your blood.
Why Does This Work
Your body will prioritize looking at carbohydrates for energy which should be readily available in two places. If you have eaten within 2 hours, you will have elevated glucose levels in your blood (your post-meal blood sugar spike). The second location is the Glycogen in your liver and muscles. Once your body has burned your glycogen and glucose, it only has fat left to burn for the energy you will feel your energy levels deplete as this can only be achieved through aerobic metabolism at a lower rate.
Anaerobic metabolism is inefficient and therefore, expends about 13 times more calories, to make the same amount of ATP for your body to burn. Even though anaerobic metabolism doesn’t burn fat, there is still oxygen circulating around your body targetting fat at a steady rate. The increased carbohydrate energy burned will mean that your body does not have as much excess if any to store as body fat. As long as your eating habits allow, your body will burn more fat at a later time.
There is also something called Excess Post Exercise Oxygen Consumption (EPOC). This study describes EPOC as an afterburn period where you are using more energy than is required at resting levels. The study shows the effects of EPOC are relative to the level of effort during exercise. Basically the harder you work while you exercise the more calories you will burn for anywhere between 15 minutes and 48 hours after exercise. If the calories are burned due to increased oxygen consumption, then some of this oxygen may be burning body fat directly.
Finally, it’s like a workout for your heart. Cardio conditioning will make your heart stronger and a stronger heart is more efficient. You can pump more oxygen around your body meaning you will perform better at future workouts, including your fat-burning walks.
Reaching Your Cardio Zone
If reaching your cardio zone is physically more difficult, it is easier to understand. Push as hard as you can, stop, recover, start again. Due to the low impact of walking, it can often be ruled out as a good cardio exercise. However, powerwalking, uphill walking, and Nordic Walking are all effective to raise your heart rate enough to be considered cardio.
The high intensity of your cardio zone makes it unsustainable for longer periods. Therefore a popular way to use this zone is by interval training. Put everything you have into a powerwalk over 200 meters and see how you do. If this is challenging, slow down for 200 meters and then speedwalk again. I find it easier to get my heart rate up with walking poles. The increased speed and the full-body movement of Nordic Walking make it easier for me to increase my heart rate.
The Benefits Of Walking In Your Cardio Zone
- Highest calorie burn rate whilst exercising
- Exercise can be completed more quickly
- EPOC or exercise afterburn resulting in more calories burned after exercise
The Cons Of Walking In Your Cardio Zone
- Physically more difficult to reach the required BPM
- Increased recovery time
- Your energy levels deplete when your body runs out of carbohydrate energy
Fat Burn Vs Cardio – Heart Rate Management
In the context of exercise, you hopefully will now have a better understanding of the difference between Fat-Burning and Cardio settings on your smartwatches. If you own or are interested in purchasing a smartwatch to manage your health and fitness data, you can utilize the connecting app to review your heart rate.
When I log my walking activities, my Garmin Connect app tells me how long I spend in each heart rate zone so I know what kind of energy I used the most. I can compare that data to my incline and my distance over time so I know exactly what speeds and which inclines will cause my heart rate to rise to which levels.
However, you should listen to your body, if you start to feel pain, slow down. If walking is too easy, speed up. You will begin to grow and change with your routine with or without a smartwatch.
Fat Burn Vs Cardio – Who Wins
It really depends on what you are trying to achieve from your workout. If you are pushed for time, 30 minutes of anaerobic cardio conditioning will burn more calories than a 1-hour consistent fat-burning walk.
However, if you are looking for low impact or you are on a lower calorie diet, you might prefer the fat-burning zone to trim your waist.
If you are a maths person, you may prefer to utilize the fat-burning zone as you can objectively work out how effective your weight loss can be. It is thought that 1lb of fat stores 3500 calories and therefore if you can increase your calorie burn rate by 3500 per week in this zone, you can target 1lb per week weight loss. (remember that 1lb relates to fat loss, your muscles may increase in weight, skewing your overall results, but this is ok)
In fact, this study compared the fat burning effects of moderate-intensity activity to higher intensity activity, in obese women and returned comparable results. Either is effective as long as you manage your diet as well.
Maintain A Varied Walkout
I recommend a variety of intensity across your routine, choosing your levels based on your overall targets, your physical situation, and your schedule. By maintaining a varied routine you will find that your sessions complement each other allowing you to perform better and achieve better results overall.
Whichever heart rate zone you utilize, being aware of how your body processes your energy can really help you optimize your walking for health goals.
Did you find this article helpful or would you like to share your routine? If you would like to weigh in on fat burn Vs cardio, Join the discussion and add a comment below.