What is the best way to lose weight for your age?
Discuss: as you get older, you can do less intense exercise but still get the same the same fat burning or cardiovascular results compared to when you were younger.
Answer: Yes, believe or not. But also no and, ultimately, no. Read on to see what this means.
Maximum Heart Rate
Maximum Heart Rate (MHR) is a generalised number that decreases every year that suggests the maximum beats per minute your heart should beat when your body is working at its maximum capacity. Whatever your MHR, you should not look to work above this level – if at all, this should not happen for more than for 30 seconds a day unless in a professional athletic environment.
Maximum Heart Rate (MHR) calculation:
MHR = 220 – age
– A 20 year old will have a MHR of 200 beats per minute (bpm)
– A 40 year old will have a MHR of 180 bpm
– A 60 year old will have a MHR of 160 bpm
Workout your maximum heart rate and then divide it by 2 to find 50% of your maximum heart rate for two figures to refer to throughout this article.
Why do we care about MHR?
Everything that we do, from sleeping to walking to running, works in relation to you MHR. All actions require the heart to pump blood around the body to provide oxygen to our tissues to perform tasks each second. The more intense an activity and the more stress that is put on the body, the more oxygen is needed. The more stress that’s put on the body, the quicker the heart beats in trying to provide more oxygen to the body’s tissues to continue to provide fuel to complete the required actions. Thus, the more intense an activity, the closer your heart rate gets to reaching its maximum heart rate.
This is why it is generally easier to be more active and put the body under more stress when you are younger because it has a higher heart rate range to work with before the heart-rate-raising activity reaches an intense and non-sustainable level of 80-100% of your MHR.
Thus, the older we are, the easier it is to get close to the Maximum Heart Rate and put excess stress on the body. This is because your resting heart rate – the slowest your heart beats during the day – doesn’t drop noticeably as you age like your MHR. Your resting heart rate will stay around 40-80 beats per minute depending on your fitness level and natural heart functionality.
Workouts zones and heart rate
The higher the intensity of the activity, the greater the amount of energy and oxygen that is required to perform it – and the quicker the energy and oxygen is needed to be provided too.
Foods that we eat are stored in the body in different ways. The energy from these stores is then used in different amounts depending on the intensity of the activity that is being performed.
|Intensity||% of MHR||Generalised energy sources||Workout zone||Level of calories burned per hour|
|Sedentary||25-50%||90% fat – 10% carbohydrates||“Resting”||Low|
|Low||50-65%||60% fat – 40% carbohydrates||“Fat burning”||Medium|
|Medium||65-80%||40% fat – 60% carbohydrates||“Cardiovascular/aerobic training”||High|
|High||80-100%||20% fat – 80% carbohydrates||“Anaerobic training”||Highest|
All of these figures in the table are appropriate for all age groups. The precision of the energy source figures is dependant on the level of fuel every individual’s body has at that present moment – depending on the time lapsed since the last meal as well as the type of meal consumed; at times we can also see muscle protein used as a source of energy when fats and carbohydrates are depleted. Generally speaking, these figures and zones are relevant for any age and any fitness level.
IMPORTANT – the ‘Fat burning’ workout zone
The more sedentary the human body, the more body fat is used as the energy source. So when you are sitting down, it is your stored body fat that is being used nearly 100% as an energy source to allow you to function On the face of it, this is great news for fat loss and for lazy people worldwide – sit down, and you are solely burning body fat!
But it’s not quite as simple of that of course because the less intense the activity, the fewer calories that are being used. So even though 100% of the calories used when sitting is coming from stored body fat, this may only mean 70 calories per hour. Moreover, you can of course be adding to your body fat storage as you eat and, unless on a very controlled diet, the rate of body fat storage from the food eaten can easily exceed the rate at which body fat is being used for energy. Exercise and being active is encouraged to increase the daily calorie expenditure, making it harder to over-consume calories on a daily basis and put on fat – unless you eat the wrong types of food of course which can promote a more rapid fat storage.
The more intense the activity, the more carbohydrates (stored glycogen in the liver, blood and muscles) are used as the energy source. Also, the more intense the activity, the more calories burned per unit of time. So even though only 40% of the energy source used in cardiovascular exercise (65-80% MHR) comes from stored body fat, if the exercise burns 700 calories in an hour, then 280 calories of body fat will have been burned for energy – quadruple the amount compared to sitting still and burning 100% body fat at 70 calories per hour.
The ‘Fat burning’ workout zone is called ‘Fat burning’ not because it provides the most efficient body-fat-usage intensity nor the greater number of calories used from body fat per hour, but because it provides a middle ground where a more-easily continuable exercise intensity provides a large proportion of calories burned from body fat whilst still burning a good amount of calories per hour in total.
Remember though, because the ‘Fat burning’ workout zone has a lower intensity of exercise and a lower calorie expenditure compared to high intensity activity, you will have to perform the activity for an extended period of time (normally 35-50 minutes) to burn a good amount of calories from body fat and to create a calorie expenditure to noticeably count towards the overall daily calorie deficit (calorie output > calorie input).
The take home message in this section is: although 100 beats per minute may have been in your “Sedentary” or”Fat burning” zones when you were 20 years old at around 50% of your MHR, when you are 65 years old, 100 bpm is actually 65% of your MHR and is in your “Aerobic training” zone.
Exercise, heart rate and the ageing process
To showcase what this means, if we take a scenario where we say person A’s fitness level (an arbitrary measurement) does not change from the age of 25 to 60, but obviously their maximum heart rate reduces annually due to the natural ageing process, we can see that it takes a less intense activity to enter a higher ‘Workout zone’ as you get older.
With the same fitness level between 25 and 60 years old, we would expect the same activities will cause a similar increase in heart rate at both ages. Thus, in order to hit the same ‘Fat burning’ workout zones, a 25 years old may have to run to get the heart rate up to 60% of its maximum (127 beats per minute), whereas at 60 years old the heart rate would only need to get to 104 beats per minute to be at 60% of its maximum, a brisk walk.
Furthermore, if we say that this time person A’s fitness reduces from the age of 25 to 60, it will take an even lower level of exercise activity to reach the ‘Fat burning’ and other workout zones! So if a fast run left your heart working easily at 127 beats per minute because of good fitness when you were 20, you could only need to climb a flight of stairs for 10 seconds to get your heart to the same MHR percentage as you age if your fitness has decreased.
Take home message from here is: if your fitness stays the same or if it decreases as you get older, you will actually need to perform less intense exercise in order to hit the different workout zones which are based around a percentage of your Maximum Heart Rate.
But…it’s not actually good news for 40+ people
This so far is wonderful news for 40+ individuals everywhere with a mid-life belly. On the face of it, what I have said to you so far is “Don’t run as you get older, just walk. You’ll be in the same fat burning zone as when you ran when you were younger, but without the effort.”
But, let me take you back to an earlier concept. The lower the level of exercise intensity, the less calories burned. The penny may drop at this point with a forlorn expression on the 40+ individuals’ faces.
Even though working at a lower exercise intensity as you get older means that you are entering the same workout zone based on a percentage of your MHR as when you did higher intensity exercise when you were younger, this doesn’t meant that the amount of calories burned matches the workout zone. The workout zones above – Fat burning, Aerobic, Anaerobic – are based around a percentage of the Maximum Heart Rate. But, the total calories burned for an individual undertaking exercise correlates with the actual mechanical intensity of the exercise NOT it’s output in relation to your age.
For example, person A – a 25 year old – and person B – a 60 year old – can both run 5km in 30 minutes. They have the same weight and muscle mass, and each run this distance weekly declaring themselves as ‘fit’. They have a similar average heart rate of 127 bpm running this distance. From this, these two individuals will burn a similar number of calories when running this distance because their muscles and respiratory system need a similar amount of fuel to perform this activity – let’s say this is 300 calories. However, the energy sources for each individual to use these 300 calories will differ.
127 bpm is 65% of the MHR for the 25 year old (in the ‘Fat burning’ workout zone with 60% of the calories coming from stored body fat) but it is 80% of the MHR – on the Anaerobic workout zone boundary using 80-90% carbohydrates – for the 60 year old. This means that this run is a more efficient fat burning tool for the 25 year old as they would have burned 180 calories from stored body fat. The 60 year old would have only burned 60 calories from body fat, would have put their body under more strain because of their age-related Maximum Heart Rate and, without abundant carbohydrate storage, would have used protein sources (their muscles) to make up the energy requirements leaving them with less muscle mass than before the run.
For the 60 year old to have 60% of their energy source coming from body fat, they would need a heart rate at 104 bpm – a brisk walk. But a brisk walk, even though it is in the right heart rate and workout zone for optimal fat burning, will only burn 150 calories in that time equating to 90 calories coming from stored body fat. For the 60 year old to burn the same amount of calories from stored body fat, using the same workout zone as the 25 year old and to not put their body under unnecessary strain, they will have to walk briskly for an hour compared to the 25 year old’s 30 minute run.
Other things to remember
As you get older, your muscle mass reduces naturally. With less muscle mass, you will burn less calories at rest compared to someone who is younger with more muscle. Thus, your daily calorie expenditure looks to naturally decrease when you get older too.
Also, because it is not encouraged to tax your heart at the higher levels of its ability when you get older, you shouldn’t regularly perform the intensive activities that would have burned many more calories per minute that you did when you were younger. Remember that less intensive activities will take your heart rate closer to or even over your age-related Maximum Heart Rate as you age.
Couple this with the sedentary nature of many adult jobs and the ease at which you can put on weight over the summer or a holiday period though excess (and the wrong type of) food and drink consumption, and you can see why it is harder to lose fat as you get older and much easier to put it on.
In short, a decrease in calorie expenditure (naturally, circumstantially and through not taking the heart rate as high as it used to) means that it is easier to gain weight through a continual daily calorie surplus as you get older. Moreover, once the weight has gone on, it is harder to lose it because activities that provide greater calorie expenditure become more limited as you age. Plus, exercises that work directly in the ‘Fat burning’ workout zone require a longer duration in order to get the same calories burned from stored body fat compared to the shorter, more intense activities that you used to perform when you were younger.
So my piece of advice ageing and not putting on fat is go for lots of walks and healthily active with yoga, resistance exercises and aerobics classes; but moreover, it becomes even more necessary to watch your diet. To lose weight, it is easier to create the necessary calorie deficit and control weight gain through your diet than it is to use exercise as each year passes. Because of your natural decrease in muscle mass – resistance training actually looks to slow this process, which is why it is recommended – you should also decrease portion sizes as you get older too but with keeping protein intake at a higher level. Gentle to moderate exercise will of course help you to increase the calories expended per day too, so the best combination is for a controlled diet and a regular exercise pattern with just ‘staying active’ being a buzzphrase every day.
So, youth of today, enjoy the days where a 30 minute run can undo the indulgence of the night before for efficiently burning fat and excess calories. When you’re 40, 60, 80 it just won’t be the same. For those who are 40+, workout what is the best combination to suit you to manage your weight.
Director, Head of Fitness and Nutrition
Fitness Body Pro