My tracking for fitness is currently based on a 28 day (4 weeks) time window. For example, my goal is to have 3 high intensity exercises per week which means that over the four weeks, it should be 12.

The same is for all kind of physical exercise (walks, longer bike trips etc.), recovery exericses (yoga, etc.). See the dashboard below: enter image description here

My question is: Based on experience and research, is the 4 week time window too short? The argument for a longer period would be that you capture longer trends, the argument against is that it if it is too long, the motivation for seeing changes decreases. Also, too long of a window might not capture the actual impact of training.

My overall health goal at this time of the year is not connected to a specific event.

  • 1
    What attribute do you want to track? Strength, endurance, cardio? Why can't you track them over a month and other time periods? Commented Oct 3, 2013 at 19:58
  • 3 Months, 6 Months, Year, Decade. Such a short window is only useful for a beginner who isn't engaged in any activity.
    – user8271
    Commented Apr 1, 2014 at 22:44
  • Given this answer, see fitness.stackexchange.com/a/16244/3778, it seems like the longest residual effect is thirty days -> having a longer time period is of low value.
    – FredrikD
    Commented Apr 26, 2014 at 12:19
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    Based on my recent Runkeeper records (~2+ years) I'd say having more data is definitely useful for spotting trends
    – Ivo Flipse
    Commented Jun 1, 2014 at 7:14
  • @FredrikD The point of long-term tracking is in no way limited to supercompensation from individual workouts. There are plenty of scenarios in which one might need much more than 30 days to track the utility of a new training regimen. Commented Jun 1, 2014 at 11:07

3 Answers 3


In general, the body adapts to new stress loads (i.e. workouts) at a rate of approximately 50% per week. So, after 4 weeks, your body will be approximately 95% adapted to the new workload. By "adapt" I mean build muscle tissue, increase capillary density, more efficiently generate ATP, etc. If you start a new workload, they progression of adaptation over 4 weeks will be:

Week 1: 50% Week 2: 75% Week 3: 87% Week 4: 95%

In endurance sports, however, coached athletes typically do not keeps the same workload over a whole 4 week period. Instead, it varies cyclically with a general upward trend designed to stimulate continued adaptation, even after 4 weeks.

Therefore, I prefer tracking fitness progress over more than a four week window.

  • Could you provide some links to studies or evidence for some of that?
    – Eric
    Commented Nov 16, 2014 at 0:26
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    Great input! The rate of adaption you mention feels about right based on my N=1 observation over the last year. I my system, changing from 4 to 6 or 9 etc is no problem. However, I have learned that it is much better to have a rolling window than following calendar weeks/months
    – FredrikD
    Commented Nov 16, 2014 at 13:16
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    Eric, I believe that I picked this up from one or both of these books: Triathletes Training Bible (Joel Friel), Triathlon Science (Joel Friel).
    – klsoren
    Commented Nov 18, 2014 at 0:16

Very good question.

It totally depends on your current status:

  • Age.
  • Physical fitness.
  • Metabolism.
  • How long you take to recover. Etc.

To track your fitness is an on going process. It changes with your fitness and time. I would say 15 to 20 days should be good enough for the activities you have mentioned.

There are some activities which are not measured in days, but in how many repetitions you do.

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    Could you elaborate a bit more on how your vector {age, ..} impacts the time window?
    – FredrikD
    Commented Sep 20, 2013 at 7:52

I would say you are trying to do is an objective analysis on your health, if there's no related...Which I would say the following describes as what you may want to try:

It sounds like what you want to do is record this data over a year or half of a year. Tracking your caloric intake is something that requires a much shorter duration, but for diagnostics regarding your fitness levels (i.e. fat content, and say stress levels) these can be increased or decreased in a matter of days or weeks. With fluctuation like that it's going to be hard to say my training improved this area of my life, unless it's across a broader scale. Scale out into a larger time frame, and you will be able to see conclusive trend based on the past 6-12 months of hard dedicated work, any fluctuation in the meantime would be insignificant to your overall goal.

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