How quickly a person loses their muscle strength and definition really depends on a number of contributing factors, such as how fit they were to begin with, how long they have been training for, how old they are, and what caused them to stop in the first place (illness or injury places your body under extra stress). The bottom line is that though rest days are actually an integral part of maintaining, or developing, muscle strength and definition, any prolonged period of inactivity will result in muscle loss, and usually faster than you might think!
So, let’s have a look at what you can roughly expect if you stop exercising for a prolonged period of time:
Losing Strength: For the average person, you will start to notice a loss in strength and definition within 2-3 weeks of inactivity. This doesn’t mean that it takes this long to start taking effect, only that it is usually this long until you start to really notice it. The problem is that gaining back what you lost will take you a lot longer than it does to lose it in the first place!
Losing Cardio Endurance: For those of you who are avid joggers, or regular spin class enthusiasts, and you have gone away for a few weeks, you will have probably noticed a significant drop in your fitness levels. This is because we tend to lose this type of conditioning a little faster than we lose our strength. Don’t worry though, you will also be able to gain it back a little quicker than you will your strength, as long as you are consistent when you get back into it!
If you have been exercising for a long time, and you have a high level of fitness, you will notice that you maintain your strength and cardio endurance a little longer than others. If you are quite new to exercise then you could notice a loss of up to 80% of your fitness in little over two weeks!
What You Can Do: If you know you are about to have a break from your exercise regime, whether it be because of a holiday, or due to an injury, then there are ways in which you can help reduce your loss of fitness. The most basic one is simply this: Just because you are not training, doesn’t mean you have to sit around and do nothing! Try to incorporate as many activities into your day as you can, such as walking, swimming, dancing, cycling or basically anything that gets you up, moving and using your muscles!