So let’s start with the most obvious – you will lose muscle.
This is because your muscles will decrease in size if you don’t regularly expose them to the amount of stimulation that they require for maintenance.
Muscle costs your body a fair amount of energy to maintain. So, if you stop lifting weights or using your muscles for calisthenics, your body will become “very tempted” to save that energy by getting rid of some of that muscle.
Unfortunately, the research on exactly how quickly you’ll lose muscle mass is a little mixed.
Some studies suggest that muscle atrophy occurs within just two weeks of detraining. (1) Others suggest that atrophy is more likely to occur within three to six weeks. (2)
Results are so mixed, mainly because many different factors influence how fast you’ll lose muscle.
Examples include your protein intake, your daily calorie intake, and your overall activity levels throughout the day aside from exercise.
Another thing that further complicates the situation is the fact that muscle glycogen stores are lost very quickly when you stop exercising. (3) I’ll explain.
After you eat carbohydrates, they’re broken down and stored in your muscles as glycogen and they’re stored along with a fair amount of water.
When you stop working out, and your muscle glycogen stores go down, your muscles will visibly shrink since there will be less water retention inside of them.
This is important to note because when scientists measure muscle loss, they look at things like fat-free mass, lean body mass, and fiber cross-sectional area.
They do that with medical tools and tests like muscle biopsies, DEXA scans, or MRIs.
But the problem is, even though these methods are useful, they are affected by the amount of glycogen stored within a muscle.
In other words, when you have less glycogen in your muscles, the measuring methods employed will interpret that as lost muscle mass.
In reality, you simply stored less glycogen and water within your muscles. And that’s why we have to take studies that measure muscle loss with a grain of salt.
Now, as mentioned, if you maintain a sufficient protein and calorie intake, it’ll take longer to lose muscle than if you deprive yourself of both.
Low-calorie and low-protein diets will definitely accelerate muscle loss.
However, as a rule of thumb, you can safely assume that true muscle loss will start to happen after about three to four weeks of not working out.
The second thing that’ll happen is you’ll lose strength. Since detraining causes muscle loss, it’s not surprising that it also decreases your strength.
After all, there’s a strong link between muscle mass and strength. For example, one study found a strong relationship between chest size and bench press strength. (4)
In powerlifters, there’s a 86-95% correlation between fat-free mass (in other words muscle mass) and performance with the major lifts like squats, deadlifts, and bench press. (5)
Luckily, we have a systematic review involving over 27 studies that can help us understand how fast you’ll lose strength after detraining. (6)
This review found that maximum strength levels can be maintained for up to three weeks after stopping resistance training.
After that, you’ll start experiencing a gradual decline in strength and the rate of strength losses will accelerate between 5-16 weeks after stopping exercise. (7)
So, it’s not that big of a deal in terms of strength if you’re forced to take just a few weeks off due to something like an injury or being busy with work or exams.
And it’s also true that taking a few weeks off doesn’t impair long-term strength gains.
This can be seen clearly in a study where participants either trained for 24 consecutive weeks or alternated between six-week periods of training and three-week periods of no training. (8)
And as you can see in the graph from the study, there was very little difference in strength gains over the long run between the two groups. (9)
So, bottom line – taking a few weeks off won’t hurt strength too much. But when those few weeks turn into a month or longer, you may have to start worrying.
#3 Mind you… muscle memory
Luckily one beneficial side effect of stopping your workouts is that you’ll be able to take advantage of muscle memory.
So even though you will lose muscle and strength after about a month of detraining, the good news is that you can regain both the muscle and the strength much faster than what it originally took to build it in the first place.
Here’s how it works. To grow a muscle beyond a particular size, your body has to add myonuclei to the tissue. Myonuclei are responsible for regulating most cell functions within muscles.
You can imagine these as the centers of each of your muscle fibers.
Now it’s a time-intensive process to add new myonuclei to a muscle, which is why you can’t gain twenty pounds of muscle in a short time period, like a month.
The speed at which your body can add new myonuclei is called “myonuclear addition” and it determines how fast you can actually build muscle.
The good news is that once those myonuclei are in place, they tend to stay there.
Research indicates that when it comes to human muscle tissue, even after extended periods of detraining, the same myonuclei will remain there for 15 or more years. (10)
Some people even claim that myonuclei will remain in place for your entire life.
This is why it takes much less time to regain lost muscle and strength, compared to what it took originally to build it. And that’s why we have a term known as “muscle memory.”
Now going back to the more negative side effects, when you stop working out your endurance will also go down.
One of the big reasons for this is that your body will become less efficient at exchanging gases within cells.
Indeed, when you stop working out you’ll experience a reduction in the number of alveoli in your lungs. These are tiny air sacs in your lungs that take up the oxygen that you breathe in.
This is why alveoli are known as the workhorses of your respiratory system.
Another reason why you’re endurance will go down is because you’ll have fewer capillaries in your lungs, and this is bad because they supply the alveoli with blood.
This is part of what leads to a decrease in blood volume and a reduction in red blood cells.
Ultimately this translates to a reduced ability to carry oxygen to your muscles and clean out the carbon dioxide from your body.
When you stop working out your heart muscle will also get weaker. This means your heart will pump less blood volume throughout your body, requiring more pumps to achieve a well-balanced circulation.
This leads to a reduction in your VO2 max, which is the maximum amount of oxygen that your heart, lungs, and muscles can effectively use during exercise. And when I say exercise here I mean anything from walking to sprinting.
So, when VO2 max goes down, you’ll be out of breath sooner and your muscles will fatigue earlier. This will prevent you from performing in the same way that you could before you took a break from working out.
Interestingly enough, according to some studies, your VO2 max will decline slower the more athletic and active you are and have been in the past.
Highly trained athletes that stop training for about a month should only experience about a 6-20% decline leaving their VO2 max still well above the average inactive person.
Meanwhile, people that recently started training or people that constantly yoyo between training and then skipping, will most likely completely reverse any gains they made with their VO2 max and their endurance, bringing them back to square one.
When you stop working out your sleep quality and quantity will go down. An amazing yet often overlooked benefit of regular exercise is that it helps you get to sleep faster and stay asleep for longer.
That, in turn, offers countless benefits. These include improved concentration, enhanced insulin sensitivity, and a reduced risk of heart disease.
It’s proven that even people with bad sleeping problems can highly benefit from exercise.
For example, one study on people with insomnia found that the participants slept, on average, 45 minutes longer per night after four months of regular exercise. (11)
Moreover, according to the National Sleep Foundation exercise improves sleep quality even for people without sleeping problems like insomnia. (12)
Now, unfortunately, it also works the other way around. If you don’t exercise, you tend to get worse sleep quality.
As you can see in the graph below, about 44 out of 100 people who are inactive experience fairly bad or very bad sleep quality, as opposed to just around 17 out of 100 people who exercise vigorously. (13)
So, bottom line – if you stop exercising, don’t be surprised if you find it harder to get to sleep.
Another obvious issue that you’ll face when you stop working out is you’ll be more likely to gain body fat.
The main reason for this is straightforward – you’ll burn fewer calories. This means you’ll be more likely to end up in a calorie surplus and gain fat.
However, aside from the obvious, there are other reasons why you’ll be more likely to gain fat.
One is that, as I just mentioned, the quality and quantity of your sleep will go down, which increases your chances of gaining fat while also increasing your risk of muscle loss.
Another reason why you’ll be more likely to gain fat if you stop working out is that you’ll likely also start to slack off in other areas of your life, particularly your diet.
You may have experienced this at some point already. Even though you may feel motivated to eat clean when you’re consistently putting in the work and hitting the gym, that motivation will fade away when you stop exercising.
This is because most of us have an “all-or-nothing” mentality. So, when you quit the gym you may also be more likely to replace your healthy salad with a big mac.
#7 Blood pressure increase
The next problem that you’ll run into is that your blood pressure will increase.
It’s well-known that being sedentary is bad for your heart health and one reason for this is that simply being inactive tends to lead to higher blood pressure.
And if you’ve already been working on decreasing your blood pressure you may find it alarming that blood pressure will increase back to pre-training levels after just two weeks of stopping exercise. (14)
This happens for a couple of reasons, including the fact that being sedentary stiffens the arteries. This in turn means that your heart will need to pulse the blood more forcefully for it to reach your whole body.
Aside from that, I already mentioned that discontinuing exercise often also causes other bad habits to develop, such as consuming more junk food or just being lazier in general.
Both of these are detrimental to heart health.
#8 Psychological consequences
Last but not least, when you stop exercising not only will you be hurting your muscles but you can also hurt your brain.
There are actually a whole bunch of adverse side effects that’ll happen to your brain when you stop exercising.
For example, your mood may worsen. This is because when you exercise, your body produces endorphins, which are feel-good hormones.
Your body also produces other happiness-inducing chemicals like dopamine, serotonin, norepinephrine, and endocannabinoids.
The effects of exercise on boosting your mood are so powerful that research even suggests that exercising can be as effective as prescription antidepressants. (15)
When you stop working out, you’ll no longer get the same mood-boosting effects, which can create more depression and anxiety in your life.
The other issue is that blood flow to the brain will decrease. (16)
When researchers examined cerebral blood flow in physically fit older adults, they found that just 10 days after stopping exercise, blood flow decreased by 20-30% in eight brain regions.
These included the left and right hippocampus, which are both responsible for learning and memory. So you might become a little less sharp after stopping your workout routine.
In fact, according to an interesting study on twins, it’s very likely that you experience more cognitive decline without exercise.
In this study, they took 10 pairs of identical male twins that exercised regularly. They had one twin in each pair stay active throughout the study, working out just twice per week. The other twin exercised less.
After three years, the results showed that the more sedentary twins had less grey matter, which is the tissue in your brain that’s crucial for processing information. (17)
So contrary to the popular quote “all brawn and no brain”, it turns out that brawn and brain can go hand in hand since exercise doesn’t only help you build muscle but also supports your brain’s health.
So those are 8 things that’ll happen when you stop working out. I’m sure it’s no secret that I’m hoping that this article convinces you to continue working out or to only take a short break if necessary.
That’s because there is truly nothing out there that can provide the lifestyle benefits that exercise can.
Not only does it add years to your life but it also adds life to your years.
Taking a short three-week break or a month off the gym can often lead to a downward spiral where you don’t find yourself back at the gym until 15 years later.
I’ve met many people that have regretted taking long periods of time off. So I encourage you to treat exercise like brushing your teeth.
Even if you’re stuck without a gym, you should find a way to do it.
Now, if you’re struggling with developing a program that you can do at home, I can definitely help you with that.
If you’re getting demotivated because your current program isn’t getting you the results you want, I can help you with that too.
So, if you want to eliminate all the guesswork and get a done-for-you, proven plan to pack on pounds of muscle while burning away your stubborn fat check out the link below. Let me help you stay on track.
We’ll make sure that you get a full workout plan, a customized diet plan based on your preferences, and a coach to help you 24/7 whenever questions or issues come up.
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- Muscle atrophy occurs within just two weeks of detraining.
- Atrophy is more likely to occur within three to six weeks.
- Muscle glycogen stores are lost very quickly when you stop exercising.
- There is a strong relationship between chest size and bench press strength.
- In powerlifters, there’s a 86-95% correlation between fat-free mass and performance with the major lifts like squats, deadlifts, and bench press. https://link.springer.com/article/10.1007/s00421-001-0543-7
- Show the following paper:
- After three weeks, you’ll start experiencing a gradual decline in strength and the rate of strength losses will accelerate between 5-16 weeks after stopping exercise.
- Taking a few weeks off doesn’t impair long-term strength gains
- There was very little difference in strength gains over the long run between the two groups.
- Myonuclei will remain there for 15 or more years.
- Participants slept, on average, 45 minutes longer per night after four months of regular exercise.
- National Sleep Foundation – exercise improves sleep quality even for people without sleeping problems like insomnia.
- About 44 out of 100 people who are inactive experience fairly bad or very bad sleep quality, as opposed to just around 17 out of 100 people who exercise vigorously.
- Blood pressure will increase back to pre-training levels after just two weeks of stopping exercise.
- Research even suggests that exercising can be as effective as prescription antidepressants.
- When quitting physical exercise blood flow to the brain will decrease.
- Study on twins. It’s very likely that you experience more cognitive decline without exercise.