Science! The Magic “Dose” of Exercise To Make Your Routine Stick

Science! The Magic “Dose” of Exercise To Make Your Routine Stick

Here’s an age old problem.

You want to go to the gym and exercise more. You hate the gym, but you love the way it feels when your body is toned and strong. So you go. And you are like, “YEAH, I’m killin’ it!” And you kick some ass.

And the next day, your body is angry.

So the next day you go back, except this time you are like “Oh my freaking GOD, make this hell stop.” And then the next day you go and say “Ugh, I’m going to skip a bunch of this, whatever, good enough.” And then you skip a few days, go again, feel pretty apathetic, and the next thing you know, you completely forget you have a gym membership until your next monthly auto payment shows up in your account.

Well, shoot.

What a whirlwind romance that was. It had all the drama of a great breakup movie. The epic meeting, the reality smack to the face, the fizzle out, and the ultimate separation. This is not a fun story. But for many, it’s a familiar one.

So – does science have the answer?

Is there a way that we can rewrite this story?

Let’s review an article that set out to answer this question (Kaushal & Rhodes, 2015). Or more specifically, the question they had was: how MUCH exercise is needed to form a new habit?

What’s the magic dose?

This duo used a bunch of fancy statistics to tackle this question. Their Canadian sample was 111 NEW gym members (i.e. just joined the gym in the past 2 weeks), and on average this group was overweight. So we weren’t dealing with those magic unicorns that are just born for the gym and haven’t met their soul mate yet. These were just regular people looking to start a new exercise routine. All the researchers did was give these people surveys at the start, as well as six, nine, and twelve weeks later.

Here’s what they looked at in the surveys:

  • Time spent exercising in each session
  • Frequency of visits to the gym
  • How “habitual” or automatic going to the gym was
  • How intentional they were about their goals
  • How INTRINSICALLY rewarding the gym was (See my primer post on intrinsic motivation. This basically means how much exercise was rewarding in and of itself).
  • How consistent they were in their routine (e.g., was it at the same time every day or centered around another daily activity like before breakfast)
  • How comfortable they were in the gym environment
  • How much mental effort went into the routine itself

OK, so, statistics statistics, statistics (that’s what I’m here for) –

Here’s what they found.

First, how habitual and intentional people were in the very beginning with their exercise routine did not reliably predict their exercise behavior later on.

But wait, this actually makes sense. Going into it everyone had intentions high – that’s what they were all there for, right? But we know, just from personal experience, that good intentions aren’t very predictive of the future (see epic saga of gym heartbreak at the beginning of this post). And, um, how can you have a habit, before you have a habit, amiright? So I get this. But later on, habit and intention DID become significant predictors of how much people got to the gym. So it wasn’t just going in blazing with high intentions, but keeping those intentions strong over the long haul that kept them going back.

But what about the magic dose?

So of all the different patterns of gym attendance people displayed, the most successful dose – meaning the dose that led to the most habitual exercise behavior over time – was going at least four times a week, for six weeks.

Four times a week. For six weeks.

And what about all those other things they measured? Well, the strongest predictor of forming a habit, at the beginning, was how intrinsically rewarding exercise was. Being more internally rewarded by the simple act of exercise from the very first day led to higher likelihood the gym would become predictable.

And over the whole trajectory of the 12 weeks? The number one predictor of forming a habit?


Just the simple act of going at the same time, or before/after the same meal or other daily marker – right after work, right before dinner, etc – over and over and over.

So what have we learned?

If you want to make your gym routine a sustainable, effortless habit:

  • Go at least four times a week, for at least six weeks
  • Go at the same time every time
  • Find a way to MAKE IT FUN, from day one. Get creative, and make the exercise feel enjoyable and rewarding.

So if you already go to the gym but lack consistency, are trying to go but struggling through every workout, or don’t go at all but want to get yourself into gear, I challenge you to this 4X6 plan – 4 times a week, 6 weeks, consistently.

When will you start your 4X6 challenge? And how will you make your next workout more fun and rewarding?

Primary Source: Kaushal, N. & Rhodes, R. E. (2015). Exercise habit formation in new gym members: a longitudinal study. Journal of Behavioral Medicine, 38: 652-663.

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