Few things have divided the fitness world as badly as the cardio debate. Morning or noon? Before or after exercise? Chocolate or vanilla protein?
There are supporters in every corner of the debate, and one thing that is clear is the fact that it leads to a lot of confusion.
So what's the right and wrong answer? Turns out, it's not as black and white as you might have been expecting to hear.
But fear not. We're here to give it to you in full color. Just sit back, and don't touch that dial (but you probably need to touch your scroll thingy).
The Case For Early Morning Cardio
Improves Fat Loss
This is probably one of the most defining benefits of doing your cardio first thing in the morning. Yes, performing cardio in the morning on an empty stomach may lead to greater fat loss compared to exercising at other times of the day.
This is likely because your body is generally more reliant on fat stores for fuel when you haven't eaten for several hours. During sleep, your body is in a fasted state, and glycogen (stored carbohydrate) levels in the liver slowly deplete and become low.
When you wake up and perform cardio on an empty stomach, your body is more likely to burn fat for fuel. Additionally, morning workouts may lead to an increased release of catecholamines (such as adrenaline) which can also help to increase fat breakdown.
Does this mean that these metabolic adaptations don't occur during other times of the day? No, but this unique metabolic state is far more unlikely to present itself.
Be sure to have some amino acids prior to cardio at this time to facilitate muscle preservation.
Introverts rejoice! Early morning cardio might be just what you want to get your cardio in, for a few reasons. Firstly, there are typically fewer people around early in the morning, which can make it easier to focus on your workout. You may not have to deal with crowds at the gym or people walking or talking around you while you exercise.
Second, you are less likely to be interrupted by phone calls, emails, or other distractions early in the morning, as many people are still asleep. This can help you to better concentrate on your workout and avoid getting sidetracked.
Finally, because you haven't yet become immersed in your daily activities, you may be more mentally present and focused during your morning workout. All of these factors can contribute to a more distraction-free exercise experience, which may make it easier to stay compliant with your workout routine.
This might be especially attractive if your 9-5 or business leaves your tank running on empty at the end of the day, but full of reasons not to work out.
When do you feel most energized? Upon waking, or in the evening? If you're truly being honest with yourself (assuming normal sleep patterns), the early morning has to be the answer.
This is true for many people as well who find that they have more energy for their morning cardio workouts compared to later in the day.
This might also be because you haven't yet become fatigued from other activities or because you have just awoken from a full night's rest.
When you wake up in the morning, your body has had (ideally) several hours to rest and recover, and your energy levels are typically higher compared to later in the day.
Additionally, the hormone cortisol, which can influence energy levels, is naturally higher in the morning. This can help to give you a boost of energy to start your day.
As the day goes on, your energy levels naturally decline due to a variety of factors, such as physical and mental fatigue, stress, diet for that day, or a sleep deficit. By performing your cardio in the morning, you may be able to take advantage of your naturally higher energy levels and have a more productive and effective workout.
The Case For Cardio Before Weights
Enhanced Muscle Recovery
Performing cardio before lifting weights can help to improve muscle recovery after a strength training session in a few ways. First, cardio exercise can increase blood flow to your muscles, which can help to bring oxygen and nutrients to the muscle tissue. This can help to support muscle recovery and repair.
Secondly, cardio exercise can help to flush out waste products that can accumulate in your muscles during strength training. This should help to reduce muscle soreness and fatigue, which can make it easier to recover between workouts.
Finally, cardio exercise can help to stimulate the production of endorphins, which are chemicals in the brain that can help to reduce pain and improve your overall sense of well-being. All of these factors can contribute to improved muscle recovery after a weight-lifting session.
May Increase Caloric Utilization
Performing cardio before lifting weights can help to increase the number of calories you burn during your workout, especially since it can help deplete glycogen stores. Cardio exercise is generally more efficient at using fat for fuel and can burn more calories compared to strength training exercises.
By performing cardio first, you can increase your overall calorie burn for the day. Additionally, performing cardio before lifting weights can help to increase your heart rate and raise your metabolism, which can help to burn more calories both during and after your workout.
This can be particularly beneficial if weight loss is one of your goals.
However, you also run the risk of not having enough energy to complete a successful weightlifting session after being too burnt out from the cardio.
May Benefit Cardiopulmonary Endurance
Do you find yourself getting winded easily from lifting weights? Performing cardio before lifting weights can potentially help to improve your cardiopulmonary endurance, which is a measure of the body's ability to sustain physical exertion for an extended period of time.
Cardio exercise can help to strengthen your heart and lungs and improve their function, which can help you to perform better during your weight lifting session. When you perform cardio exercise, your heart has to work harder to pump blood to your muscles and deliver oxygen to your body. Additionally, cardio exercise can help to improve the function of your lungs and increase the capacity of your lungs to take in oxygen.
This effect, however, should be obtained from performing cardio regardless of the specific interval, and not limited to cardio before heavy weights only.
The Case For Cardio After Weights
Improves Muscle and Strength Accrual
Performing cardio after weight lifting may help to improve strength and muscle mass accrual faster, thanks in part to a few different ways. To start, weightlifting stimulates muscle growth and strength and performing cardio after your weight-lifting session is beneficial because it may not interfere with these adaptations.
Secondly, cardio can help to improve blood flow to your muscles, which can help to bring oxygen and nutrients to the muscle tissue. This will support muscle recovery and repair, which can help to maintain or even increase muscle mass and strength. If you are into bodybuilding, such an advantage is highly sought after.
Finally, cardio exercise can help to stimulate the production of endorphins, which are chemicals in the brain that can help to reduce pain and improve your overall sense of well-being. This can help to make post-workout recovery and subsequent DOMS less intense, and potentially allow you to work out again, sooner, thanks to better recuperation.
Consumption of a supplement containing creatine and ATP is particularly useful for improving your strength and endurance, translating to more gains.
Increased Fat Burning
Performing cardio after weight lifting is a common approach employed by fitness athletes desirous of getting rid of extra body fat. Weight lifting can help to build muscle mass, which will increase your resting metabolism. This means that your body will burn more calories at rest, which can help to support fat loss.
By performing the cardio after the weight lifting, you may be able to take advantage of your body's increased calorie-burning potential and expend more calories during the cardio portion of your workout.
As previously mentioned, cardio exercise can help to improve blood flow to your muscles, which will help to bring oxygen and nutrients to the muscle tissue. In turn, this can help to support fat burning since your body needs oxygen in order to effectively burn fat.
Measuring your post-exercise oxygen consumption, otherwise known as EPOC, can help to give you a better idea of how much fat your body is burning.
Less Mental Resistance
The joy of being able to casually do your cardio after your weights is one of life's simple pleasures. Performed at other times during the day, you are required to at least put in some effort. Not so when done post-weights.
The goal at this time is to utilize the liberated fatty acids (free fatty acids) and to preserve some of the stored muscle glycogen so that you can make sure the body is not in an energy-deficient state post-workout.
If you are someone who dreads doing cardio, this might just be about the best time for your circumstances.
So Which Time Is Best?
The best time depends entirely on your goals.
For instance, if you are after the sheer largest impact on weight loss, early morning fasted cardio might be the optimal choice.
If muscle and strength gains are your main focus, but you also want to keep the heart in good working order, then you will want to focus on doing your weights first, followed by some light cardio afterward.
You will also still be poised to lose weight from this interval as well.
This way you can make sure that the muscles have been optimally stimulated for growth and recovery, whilst also taking advantage of improved blood flow and fat burning.
Performing cardio before your workout doesn't particularly serve many functions, besides the light 10-minute session that can be considered a warm-up for your weight sessions.
How Much Cardio Should I Perform Per Week?
Again, there isn't a specific number that can be pinpointed, but your goals factor heavily into this. If substantial weight loss is your goal, then 6 hours weekly aren't uncommon. On the other hand, for general cardiovascular health, 2-3 hours per week should be enough to support the heart.
Do not combine high-intensity interval training with weight training as the sheer amount of glycogen reduction that occurs can cause your blood sugar to drop dangerously low.
That, and the fact that stacking two high-intensity exercise sessions on top of each other is a recipe for injury.
Ultimately, there is no established way to determine what the single best time to do your cardio is. Your goals will factor in heavily, as would your individual body differences.
If you work at times that you might have preferred, for instance, or are unable to perform at a particular time, then cardio done anytime is better than no time at all.
If you're now starting, and unsure where to start, our best advice would be to choose one time interval, stick with it for 6-8 weeks, and determine if the results obtained are in line with your goals.