How long does it take to lose your fitness and how does it impact your body?

Here’s an insight to how your body reacts to a break from exercising, your body will respond and start to change to suit the new calorie burn or no burn.

By Bio Island Nutrition Team

Do you ever wonder when taking a break from exercising, it can’t affect you that bad? That having a few weeks off from running can’t do much damage, right? Here’s an insight to how your body reacts to a break from exercising, whether it be from becoming sick or just needing a holiday from weights. Your body will respond and start to change to suit the new calorie burn or no burn.


Studies show that your cardio fitness is what will go first. Within 14 days of inactivity, even as an everyday runner you will notice a difference when you get back into your routine. But the good news is it will only take 2 weeks of your normal routine to pick up where you left off.


It can roughly take around 3 weeks to start losing muscle and strength, but it is dependent on why you have stopped your routine. Sickness can impact muscles more quickly, while a general break won’t show any effect till about a month or longer if you have a higher fitness level. Now when it comes to building muscle back up, it isn’t as bad as cardio as we have muscle memory. Muscle memory is where your muscle cells will store data in their nuclei and from here send messages to muscle fibers to grow and store more energy. Therefore, when you begin training again your muscles have the data needed to kick into overdrive to build again.

It was believed that when you had muscle atrophy or wasting of muscles from lack of physical activity you would lose all your strength and muscles you had worked on. But as mentioned it takes time to lose muscle strength but once it has started to deteriorate you will notice muscle fatigue happens much faster, your endurance is much less and slowly your muscle definition will start to disappear.

Some other changes that will happen to your body from less fitness and activity include:

  • Gaining weight: due to muscles burning less fat and slowing of metabolism, if you don’t reduce your food intake you are more likely to gain some extra kilo’s.


  • VO2 decline: Is the measure of the volume of oxygen used by your body to convert energy from food into energy for your body on a cellular level. As you stop exercising your body will start to slowly lose its ability to effectively use oxygen or ultimately you will have a reduction in cardiorespiratory fitness.


  • Blood Sugar: your blood glucose levels rise after you eat and then drops as your muscles and other tissues absorb the sugar needed for energy. When you stop exercising your blood sugar levels remain high after a meal instead of being used by muscles. A study found that just after 3 days of no exercise that blood sugar levels remain high even in healthy individuals and over a long period of time, if levels continue to rise can lead to diabetes and heart problems.


  • Your brain: exercise has a major effect on your brain and endorphin release. Exercising helps mood control and is an effective strategy to prevent depression. Therefore, when physical activity stops over a period of time you are less likely to release happy hormones and may notice a difference in your mood and emotions.

The more exercise and physical activity you do the less likely you are to lose your fitness quickly but more over a period. There is no problem in having a break, it’s good to rest your muscles for recovery but don’t take too long. Try mixing your routine up to keep things interesting or try something new, even a new environment could be what you need to not fall off the bandwagon.


Articles you may like

Wellness Hub
Shutterstock 1660419814

Exercise for those returning to sport or at a beginner level

Depending on what you want to achieve from starting a new exercise routine is a big factor in how you go about choosing.

Read More

Getting active with kids

It may seem impossible to have time to be active or go to the gym when having children. But why not get active with them?

Read More
Shutterstock 690872620

How healthy are Australian men?

Australian men generally rate themselves as excellent or having a very good health status. But how do they actually measure up?

Read More
Shutterstock 394482010

How healthy are Australian women?

Australian women are dealing with higher levels of constant demand resulting in poorer mental health.

Read More