How Long to Form a Habit? The Real Science (Not 21 Days)

If you’re on a path to adopt healthy habits you may be wondering how long to expect this process to take and how to do it the right way.  You’ve probably heard it takes 7 days, 14 days, or 21 days to form a habit. Giving the impression that if you can just stay consistent for a certain period of time you’re in the clear. So let’s talk about whether or not that’s true and how long it actually takes to form a habit.

But first, for those that prefer videos over articles you can find all the same info in this video.

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And for anyone really wanting to dive into habit change, scroll to the bottom to see some of my favorite books on habit change psychology.

What Is A Habit

Before we go much further let’s make sure we’re on the same page. In the context of wellness, many might define a habit as something we do frequently, with a set regularity, or on a specific schedule. However, not only is that not the true definition; when we really think about it, that’s not actually what we want either. For example, going to work fits the above parameters. You go to work frequently and on a specific schedule, but I don’t think anyone would classify this action as a habit.

According to the British Journal of General Practice habits are defined as “actions that are triggered automatically in response to contextual cues that have been associated with their performance”. When we consider this definition this is in fact what most of us are after. We want to wake up and automatically go to the gym or prepare our breakfast without a second thought. We want the act of focusing on our health to be instinctive.

Forming A Habit

Now you’re thinking “ok awesome now I know the technical definition but that doesn’t make me adopt those habits”, and perhaps not, but framing a habit correctly is important. It also kind of debunks the belief that doing the same thing for X days will make it a habit.

Let’s think about it this way. Say you’re training your dog to sit. If you’re only focused on repetition, well your dog likely sits down multiple times a day every day right? They should already be trained by that logic. But of course, that’s not how it works. To train your dog to sit you must set up contextual cues. You must first say the word each time your dog performs the action. This then causes the dog to respond habitually to that stimulus. Then if you want to create the habit of urgency perhaps you add a reward (verbal or otherwise) to encourage rapid response.

Now let’s apply that to your own healthy habits. If we’re focusing purely on repetition, let’s say we’ve subscribed to the 21 days belief. So for 21 days in a row, you force yourself to workout. Chances are by the end of that 21 days you’re just going to be very sore and maybe a little cranky. And as a result on day 22, you rest because, well, everything kind of hurts. Then again on days 23 and 24. On day 25 you think about it but now you’ve created the association between working out and pain, fatigue, or uncomfortable obligation. And now rather than forming a positive response to that action you’ve likely created an avoidant response. Are there exceptions to this? Sure, always, but those few exceptions are not the norm and certainly not the rule. Most people will experience or maybe already have experienced something similar to the scenario I’ve described.

Now let’s frame healthy habits with the proper definition in mind. We’ll stick with the habit being working out. So to create contextual cues we first must be more specific, for example deciding when you want to workout. So let’s say you want to work out first thing in the morning, and currently, you don’t work out at all. The first thing to consider is, ‘what instinctive response is actually required here?’ Well ideally you want your body to instinctively crave movement and for your mind to instinctively think about movement or wellness upon waking. So to train ourselves to do this we must start small, both to ease into this development and to ensure we can stay consistent from day one.

So step one may be simply stretching as soon as you wake up. Not going as far as a full stretch or yoga routine, simply moving your body by stretching your feet, stretching your neck and maybe a short back or chest stretch (depending on your normal sleeping position) Commit to this habit, and do this consistently until you feel that it becomes almost unconscious. For smaller actions like this, it may only take a week or 2.

Then you can build on this, again choosing something attainable. Perhaps you simply lengthen your stretch routine into something more formal, or perhaps your stretch leads you into a short 5-10min walk in the morning. Again apply the same principles, don’t move on until it becomes automatic and instinctive. Larger habits that require more steps (such as getting dressed, getting equipment, going outside, etc) will naturally take longer to become instinctive, it can take several weeks or months. Once you have established the habit though, you can then slowly build on them until you’ve built up to full workouts. Now of course your workouts won’t be daily, but your morning stretch can remain a daily habit to ensure you maintain the craving for movement each morning. Some mornings that craving will be satiated with a stretch and others with a workout.

If we frame habits as the result of contextual cues it becomes much easier to set ourselves up for success every time.

I often use the Pavlov’s Dog analogy when talking to my clients about habit formation and this is exactly why. Habits are something we want to crave doing and the best way to do this is to set the environment to train our brains to immediately associate morning with workouts, lunchtime with vegetables, bedtime with stretching, or whatever habits you want to incorporate into your life.

Using Habit Anchors to Form New Habits

Often when my client wants to adopt a new habit or routine I will suggest that they attach this new habit to something that is already a part of their day.  Things like brushing your teeth, showering, or eating lunch.  I call these your habit anchors.

This process is one of the most reliable ways to make a habit fit your lifestyle quickly.  The key here is you must start very small and build.  For example if you want to create a morning routine that involves meditation, yoga, making a smoothie and journal don’t try to attach all of that to brushing your teeth.

If your habit anchor is “lighter” or smaller than the new habit it will not be strong enough to hold your new habit in place.  Instead, start with something like deep breathing.

Perhaps your new habit is “every morning I’ll take 3 deep breaths after I brush my teeth”.  Eventually, the deep breathing becomes a part of that habit anchor making it strong enough to add something new like meditation or making your smoothie to it.

Why is The Repetition-Based Belief Harmful?

Let’s revisit the 21 days of exercise scenario. So you’re at day 26 and you find that after sticking with it for 21 days the last thing you want to do right now is exercise. All you can think about is the fact that it’s supposed to take 21 days to form a habit. After 21 days you should be set. It should be easy now. But that’s not what you’re experiencing. You’re left feeling frustrated, perhaps feeling like there’s something wrong with you. This works for everyone else, all the ads you’ve seen and all the influencers that have recommended this told you that it worked for all of their clients. But not for you. Now you just feel lost and give up altogether.

This spiral of negative thinking and negative self-talk is incredibly harmful to any progress. This makes you less and less interested in trying again, this is how people get stuck. While there is a small nugget of truth in the belief in repetition, it’s such a small part of the bigger picture it is unlikely to be effective for the vast majority of people. And I would argue for the few it does “work” for, more likely than not it worked because those few unknowingly created the contextual cue while committing to the habit of repetition.

I would like to close by pointing out that the tendency of fitness media to take small parts of a whole and advertise them as the whole story is largely harmful to the general public. This applies to many diet “secrets” and workout “hacks”. To those looking to adopt healthier habits please, do your research, and if you don’t feel comfortable or confident in finding reliable information seek a reputable, educated, and experienced wellness professional.

Our Favorite Book To Build Healthy Habits

Atomic Habits

The Power of Habit

Tiny Habit