You try to go to the gym most days, but then you decide to take a rest day.  Maybe a rest day turns into a few days off….and before you know it, three weeks have passed you by without one day of exercise.  Like many who take a workout break, you wonder: “Have I lost my muscles?” or “How long before I’m out of shape?”

There are lots of reasons to take a break from your workout routine — vacation, harsh weather, work demands, family obligations, etc.  Even the most dedicated fitness enthusiast may be forced to stop for a while due to sore muscles, illness, or injury.

You shouldn’t push yourself to work out every day without a break because your body needs rest and recovery days to repair muscle fibres and strengthen itself between workouts.  It’s a well-known fact that training recovery is a critical component of an exercise program, and for most people, this consists of one to three days of rest depending on intensity of the activity.

However, if you go beyond a week without activity, you begin to experience the effects of “detraining” (also called deconditioning), a phenomenon in which you lose the beneficial effects of training.  As opposed to rest and recovery, detraining is an extended rest interval that results in reduced physical fitness. 

The good news is that deconditioning is reversible once you get active again. 

Factors that affect loss of fitness

The extent of fitness loss you experience depends on several variables. These include the length of your layoff, your age and your level of fitnss.

Time away from the gym

In general, just two weeks of detraining can lead to significant decline in physical fitness.  A study from the Journal of Applied Physiology concluded that just a fourteen-day break significantly reduces cardiovascular endurance, lean muscle mass, and insulin sensitivity.

What would happen if you took an even longer break from exercise – say, 2 months? One study found that 2 months of detraining in elite athletes resulted in unfavourable changes in body composition, impaired metabolic function, and development of cardiovascular risk factors.  Although the time it takes to lose fitness levels depends on how fit you are to begin with and how long you’ve been exercising, even the most religious gym-goers will experience loss of fitness after an extended hiatus.

Age

As people age, aerobic capacity, muscle quality, as well as agility naturally decline.  It is important to exercise and stay active as you get older to preserve functional fitness.  One study looked at the effects of detraining on elderly adults, both short and long term, and found that losses in fitness gains are compounded as you age.  It’s important to track how your body is changing as you age because the loss in muscle mass and strength can decline rapidly, and soon even daily life activities suddenly become more difficult.

Level of Fitness

The fitter you are, the longer it can take for your body to get out of shape.  For example, trained athletes tend to experience more gradual declines during detraining than your regular gym goer.  For someone who works out a few times a week and is “moderately fit”, it may take two to four weeks to see significant detraining effects.  Someone who is training more intensely will take longer to experience de-conditioning.

The physiological impacts on your body

When you stop exercising, many physiological changes occur.  You begin to lose the cardiovascular gains you’ve made, such as your heart’s ability to pump blood more efficiently, your body’s improved capability to use carbohydrates for fuel, and your muscles’ enhanced capacity to process oxygen.  Any improvements you’ve seen with your blood pressure, cholesterol levels, and blood sugar may diminish. You may experience some weight gain. If you’ve been strength training, the gains in muscle size, strength, and endurance you worked so hard for will taper off.

Aerobic Capacity

It is well known that working out is good for your heart – it becomes more efficient pumping blood, and as a result, getting oxygen to the rest of your body.  When you go a few weeks without physical activity, your heart not only begins losing its ability to handle extra blood flow, your body’s ability to effectively use oxygen, referred to as VO2 max, declines.

Research shows significant reductions in VO2 max within two to four weeks of detraining, which is attributed to decreased blood volume and cardiac output.  Another study found that most of the aerobic capacity gained through exercise over two to three months is lost within two to four weeks.

What does this mean for you?  After a few weeks of sitting around rather than being active, you’ll start losing your and cardio and find yourself out of breath after climbing that flight of stairs.

Muscle Strength

When you cease exercising, you will undoubtedly notice changes in your muscles.  They will become smaller and weaker. If you’ve been doing high intensity exercise or weight training, you’ll find a reduction in your muscular endurance.

A detraining period of 12 weeks results in decreased muscle mass and muscular strength, although the muscles can return to pretraining levels.  The good news is that retraining can occur more quickly as a result of a concept known as “muscle memory”.

While strength performance may be maintained for up to four weeks of detraining, power and endurance may decline significantly in this time period as found in one study.  In another study, postmenopausal women trained with resistance bands for twelve weeks and found a significant adverse effect on their muscle power during a four-week detraining period.

The bottom line? You may maintain your strength longer than power or endurance; however, after a month of sitting, you’ll find that carrying those groceries will be a bit more taxing and you’ll fatigue quicker than before.

Blood Pressure

Lowered blood pressure is a well-known benefit of regular exercise.  In fact, exercise is a medically accepted lifestyle change to treat hypertension.  A study that looked at the blood pressure responses in a group of prehypertensive men saw a decrease in blood pressure during a six-month period of training, and a rise in blood pressure after just two weeks of inactivity.

Of course, stopping your exercise routine does not mean you will have high blood pressure.  However, if you already have hypertension, it is important to realize you may need to consult with your doctor if you’ve been using exercise to lower your blood pressure and you anticipate a period without exercise.

Blood Sugar

Normally, your blood glucose rises after you eat, then drops as your muscles and other tissues absorb the sugar needed for energy.  Exercise is an effective way to lower blood glucose levels, but if you stop working out, your blood sugar levels may remain elevated after a meal.

Blood sugar levels have been found to have remained elevated after just 3 days of inactivity in young, generally healthy individuals. (1)  The unfortunate consequence of being sedentary is that consistently raised glucose levels raise your risk of heart disease and diabetes.

The upside? Even a small amount of moderate exercise improves how your body regulates glucose and getting back to your routine will help you ward off preventable health conditions.

Fat Mass

One fear you may have is that your clothes will begin to feel a bit tight as your weight creeps up and your body goes from being toned and firm to plumper and flabbier.  Detraining has been found to have negative effects on body composition, with an associated weight gain and a decrease in metabolic rate.

A few factors may contribute to an increase in your body fat when you stop working out: 

First, your calorie requirement will decrease.  As you lose muscle mass, your metabolism slows down as your muscles lose some of their ability to burn fat.

Secondly, you’re not burning the same number of calories as you used to because you’re moving around and working out less, so if you don’t adjust your food intake accordingly, those additional calories will be stored as fat. Something you should be wary of is visceral fat aka belly fat. 

So, if you eat the same way you’ve been eating while you’re on a workout hiatus, your body won’t be burning the extra calories without an adjustment to your diet– and you will likely put on weight.

 How to Manage a Detraining Period

The best way to stop fitness losses is to not abandon exercise in the first place.  That doesn’t mean you should never skip a workout. Honour your body with needed rest and recovery.  If you train hard, taking a break will help improve your muscle development and aerobic fitness and help you avoid overtraining syndrome.

But if you’re injured or very ill, you absolutely should rest.  Life can get in the way of your normal fitness routine, but that doesn’t mean it’s the end of the world. Take time to rest and recover and get back on it when you’re feeling better. 

Here are some tips to help minimize the negative consequences of abandoning your workout schedule if you aren’t forced to completely stop exercising for an extended time:

Crosstrain or try “light” activity that’s not part of your usual regimen, such as yoga, walking, or bike rides.

Try a chair workout or add stairs to your daily routine.

Scale back your workout schedule if time is the issue.  Try just 1-2 sessions per week, break your workout into several shorter sessions, or incorporate a few sessions of high-intensity interval training.

Try working unaffected muscle groups if you’ve stopped exercising due to an injury such as a broken bone or ruptured tendon.

Maintain good nutrition while consuming adequate protein to minimize muscle loss.

Regaining fitness after a break

While it’s hard to predict exactly how long it will take you to regain your previous level of fitness, it probably won’t take as long to retrain to your peak condition as it did to become fit in the first place. Just don’t start adopting a sedentary lifestyle. 

Keeping track of your progress is a pretty vital part of your self motivation. Having a Body Composition Analysis when your ready to return is the best way of establishing a ‘line in the sand’ for your own comparison. Whether you’ve had them in the past or not is irrelevant. This is about seeing your progress from this point in time.

                                                 Contact My Body Composition Solutions for more information.

Disclaimer: This article should not substitute professional medical advice. When starting a new diet or exercise plan, always consult your physician and exercise professional first.

Information in this article has been extracted and edited from InBody USA ‘What happens to your body when you stop working out?’ byJennifer Boidy, RN is a freelance healthcare content writer from Manchester.

This post was updated on September 10, 2018, for accuracy and comprehensiveness. It was originally published on August 1, 2017.

  (1) According to a study published in Medicine & Science in Sports & Exercise

It’s a classic dilemma.

To maximize weight loss, you are tracking every calorie, substituting junk food with healthier alternatives, and cooking all of your meals at home. All of your hard work is paying off. As long as you stick to your plan and don’t cheat; the weight is just going to keeping coming off. You have already lost 10Kg and feel unstoppable!

That’s when life gets in the way.

Maybe it’s your birthday celebration. What would everyone think if you didn’t take a slice of your own birthday cake? Or your best friend is back in town and just wants to indulge for the entire day! Unfortunately, quinoa isn’t what your friend was craving for.

You’ve already made so much progress, so you think, “I can eat my cheat meals this weekend and splurge for a couple days and it won’t affect me that much right…”.

When Monday comes, you weigh yourself for your weekly weigh-in and you can’t believe it: you’ve gained 2Kg.

Two months to lose 5Kg and then one weekend to gain 2Kg. The daily morning workouts. Eating nothing but steam vegetables and skinless chicken breasts. And counting every calorie. Wasted.

First the bad news: no, your scale isn’t lying to you, you gained 2Kg. But the good news is it’s definitely not 2Kg of fat. Most likely it is nothing more than water weight.

But how do you know for sure?

Can I Gain Fat in One Day?

Let’s get one thing straight: you can’t gain a kilo of fat in a day, or even 2kg in one weekend. Biologically, it would be astounding if you did. You are very much aware of how difficult it is to lose fat quickly, but don’t laugh when I tell you, in theory, it is just as “difficult” to gain fat.

Fat gain or loss has a lot to do with your energy/caloric balance–how many calories you take in vs. how many calories you use during the day.  If you are using more energy than you take in, your body gets some energy it needs from your fat stores.  If you’re taking in more energy– eating beyond your body’s needs–then the opposite happens: you build fat stores.

A common theory in the health and fitness world is that there are around 3,500 calories stored in a pound of fat. The theory goes that if you reduce your daily caloric intake by 500 every day of the week, in 7 days you’ll lose ½ kg of fat.  Conversely, if you overeat by 500 calories a day, you can gain a ½ kg of fat in a week.

500 Calories x 7 Days = 3,500 calories/week or 1 lb/ week 

The point is it TAKES TIME to gain or lose fat.

Of course, it is much easier than you think to overeat 500 calories a day. A large blended coffee-flavoured drink once a day will do it.

In order to gain a ½ kg of fat, you would need to add about 500 calories a day on top of your normal diet, every day, for about 7 days.  This makes gaining any significant amount of fat from even the craziest all-out cheat days extremely unlikely.  

To gain 2 kg of fat in a day, you’d have to eat about 17,500 calories on top of your daily caloric limit. Not even Dwayne ‘The Rock’ Johnson can consume that many calories!

What is Water Weight?

So, if that 2 kg of weight isn’t fat, then what is it? And how long is it going to stick around?  The answer involves your body’s favourite energy source: a molecule called glycogen.

Glycogen is an energy source that is produced primarily from carbohydrates.  Your body loves glycogen because it’s an easily accessible energy source that provides a lot of energy.

Glycogen also has an interesting attribute: it bonds really well with water.  In fact, for every gram of carbohydrate in your body, there are about 3 to 4 molecules of water bonded to it. This can cause some large increases in weight, but weight due to water, not fat. Depending on what kind of diet you were on, loading up on carbs on a cheat day can increase your weight noticeably.

If you were trying to lose fat, you likely were trying to cut carbohydrates out of your diet.  It’s a very popular technique, and diets structured around low carbohydrate and low caloric intake are about as basic a diet as they come.  The Mayo Clinic notes that a diet targeting low carbohydrate intake constitutes about 60-130 grams of carbs a day.  Some popular diets – such as the Atkins Diet – target extremely low levels of carbohydrates, as low as 18 grams a day.

If you’re consuming 60 grams of carbs a day, you’re holding onto approximately 210 grams of water. That’s about half a pound of water.

But if on a cheat day, you decide to eat and drink whatever you want and load up to 300 grams of carbohydrates (the average number of carbs eaten by men (1)), you would be retaining around 1kg of water. 

If you were on a 60 carbs/day diet, you could be 700 grams heavier already.  If you went up to 400 grams of carbs, you could add on almost 1.5kg of water.

However, glycogen is far from the only substance or factor that can cause your body to retain extra water.  Excess sodium (salt), something commonly found in your favourite cheat meals, can also cause your body to hold onto the water on top of the water held onto by your glycogen.  Once you factor in the effects of other things you ate and drank, your hormones, and your unique body composition, you can see why your weight can fluctuate so much.

Once you return back to eating a low carb, low sodium diet, your body will naturally shed the extra water weight you gained.

So, Can a Cheat Day Ruin My Body Composition?

A cheat day every once in a while will not erase weeks and months of hard workouts and careful calorie counting. You can’t put on kilos of fat over one weekend.

Changing your body composition and losing weight is a long-term process, but if you do it right, you’ll have long-term results.  Quick fixes and crash diets that focus on cutting out nearly all carbohydrates for a short period don’t actually achieve lasting results, and now that you understand a little about glycogen, you also understand why.

However, this doesn’t mean you can get carried away on cheat days.

It’s so easy for your cheat day to become a cheat weekend, and your cheat

weekend to suddenly become a cheat week. Before you know it, you are

back to your old eating habits. Try a cheat meal instead and make sure you

plan a workout before to rev your metabolism.

Your body will thank you the next day.

Bottom line: it’s OK to indulge once in a while!

Making cheat days a part of your routine makes it easier for you to manage them. Just make sure after you’ve had your fun, you get back on your fitness journey and keep working towards your goals.

Disclaimer: This article should not substitute professional medical advice. When starting a new diet or exercise plan, always consult your physician and exercise professional first.

Information in this article has been extracted and edited from InBody USA ‘Does a Cheat Day Undo a Week at the Gym?” updated

on September 17, 2018, for accuracy and comprehensiveness. It was originally published on February 17, 2016.

(1)  Source US department of agriculture