How much fitness will I lose? Taking a break from running and the impact it has on your fitness.

Life happens, injuries happen and sometimes after a lengthy grueling training cycle we just need a break from running. It’s totally understandable.  The question I get from many of my athletes when discussing these bouts of time away from training is how much fitness will I lose?  This is a great question. We work so hard to reach our goals, and the thought of starting over and going through it all again can sound grueling.

I took the time to look into a few studies that addressed this question

two test tubes
Photo by Martin Lopez on

Many runners hate taking off time after a big race, such as a marathon.  Klav Madison et conducted a study on this subject. During this study, athletes took a total of four weeks off from training after their marathon race.  During this time athletes only saw a 20% decrease in VO2 max.  While taking 4 weeks completely off after a marathon isn’t really necessary, some rest and gradual return to running is a good idea.

Another study, conducted by Elizabeth Ready and Arthur Quinnery, tested the fitness decline in untrained men.  The men completed a 9 week training cycle followed by 9 weeks of inactivity. The participates saw a 70% increase in measured fitness during the initial 9 week training cycle. Similar to the decline in the first study. After 3 weeks of no training, study participants saws a 20% decline in fitness. However, the fitness decline leveled off the following weeks with a 40% loss in gained fitness, over the total 9 week period.  It is important to note, the amount of gained fitness over the initial 9 weeks was greater than the lost fitness during the time of non-training. Meaning the participants were not back at square one.

shallow focus photography of microscope
Photo by Chokniti Khongchum on

It is important to take note that the previous study was conducted on untrained participates and compare that to a third study that was conducted by Edward Coyle Et al.  This study tested the aerobic fitness on already trained athletes and rested them a total of 12 weeks. Similar to the previous study, the first 12 days saw a decline, with a drop of 7% in VO2 max and a blood enzyme test used to measure endurance dropped by almost 50%.  After this initial decline, the fitness leveled off a bit.  After the total 12 weeks of no training, the participants saw an 18% decline in VO2 max.  Notice the significant difference between athletes who have been training for a longer period of time and newer endurance athletes.

One short coming of these three studies is that they all measure aerobic fitness.  Aerobic fitness, is your endurance, including threshold and and VO2 max.  Another important component to look at is structural fitness. Structural fitness is the bodies mechanical ability to absorb  the continuous impact forces that running puts on your body. Think about how your muscles, bones, ligaments and tendons are all impacted on the run.  Returning to running can add great stress and fatigue to this structural system and needs to be addressed carefully so you do not end up side lined (again) due to injuries.

Things to consider if you need to take some time off.

  • A couple days to a week will have little to no negative impact on your training and if done infrequently can be a training advantage.
  • Maintaining fitness is easier than building. Some running is better than no running at all.
  • Newer runners will see a faster decline in fitness than runners with a longer history of continuous running.
  • If you need to take time off due to injury, consider the advantages of cross training to maintain your fitness levels.  Be sure to address both the aerobic and structural fitness. Some suggestions include
    • Aerobic fitness: Swimming, biking , aqua -jogging and AlterG Treadmill (if you have access this is a super option!)
    • Structural fitness:  strength training. Depending on the type of injury it may be best to work with a physical therapist.

      “Rest or recovery is part of training, not avoiding training.” – Jack Daniels     Photo Cred-VDOTo2 Instagram

Change the way you look at recovery. Many runners associate recovery/rest days negatively and that simply is incorrect.  Recovery is an important part of the training cycle.  Taking appropriately timed recovery can actually increase your fitness levels and decrease your likelihood for injury.

When you are ready to return to running,  do so gradually and listen to you body.

Thanks for reading! Be sure to like, comment and subscribe! 


Need a coach to help you reach your running goals?

VDot certified! I am a VDot  Certified coach with over 11 years of coaching experience! I have worked with young beginners in the middle school level, high school athletes who have gone on to compete at national Division I championships, and adults runners of all abilities.   For more information click here




Published by RunCanvas

Avid Runner, mother, wife and teacher. On a wonderful journey, taking it one mile at a time.

2 thoughts on “How much fitness will I lose? Taking a break from running and the impact it has on your fitness.

  1. This was a great post. Well researched! It’s good to hear taking small breaks won’t cause a major decline in fitness. I personally have scaled back my running but short runs in better than no runs now that I am expecting! Cross training too is my new go-to. Glad to know that after baby I can get back to where I once was.


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