Why are sleep habits so hard to change? [part five]

In an effort to not be tired-all-the-time, a few years ago I figured I’d start taking a morning walk. Such a habit may come naturally to some – those with a dog to walk or morning commute may have no choice. But for a night owl who works from home? Going outside can be hard. Still, knowing the benefits of both morning sunlight and moving my body, I set out to change my behaviour. Years later, I really look forward to my morning coffee walk and podcast to get the day going.

Many of us have aspirations for crafting our evening routines. Perhaps we’ll start reading! Knitting! Listening to a meditation! Okay, I’ve intentionally overused exclamation points here, as we often approach these changes with verve(!). However, many of these habits don’t come to pass.

When we don’t form this new, desired habit, and often end up back on our devices, it can feel deflating. We often assume it’s a willpower problem. But what if evenings themselves are the problem? Research suggests that evenings are just hard. And it may be harder to form healthy habits in the evening than any other time of day.

In one 2017 study, researchers followed 48 students attempting to form a new habit – stretching their lower back and hips. One group were randomly assigned to stretch in the morning, the other in the evening before bedtime. The morning group managed to form a new habit after 106 days, about 3.5 months. But the evening group took much longer: 154 days. Just over 5 months.

What the researchers believe was behind this difference is something you’ve probably never thought of when considering your own habits. It’s cortisol. Cortisol – typically referred to as the “stress hormone” – is thought to play a role in habit development, influencing processes involved in attention and learning. Cortisol typically has a natural circadian rhythm, where it’s highest in the morning and declines toward the evening (assuming you’re not a nightshift worker or extreme night owl). In the study, researchers measured cortisol in saliva at different times of day, and cortisol helped explain why morning habits form faster: the more cortisol people had while stretching, the sooner this behaviour became automatic.

More research supports this idea that morning routines are more stable. We’re more reliable taking medication in the morning compared to the evening. People are more likely to follow a plan to eat fruit and veggies earlier in the day. Forming a meditation habit is more likely to stick in the morning. When we wake up, we’re creatures of habit, while evenings are more susceptible to the whims of our messy, modern lives.

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Now, for those of us out there who want to form evening habits that help support our sleep, it’s not all bad news. There’s an important nuance. Everything above is about forming a habit – the context, the repetition, the overall learning process. And, yes, forming habits at night may take more effort. But once a habit does take hold, evenings can actually work in your favour. Because of this general fatigue and frazzled cognition, we tend to rely on habit more in the evening.

A new study led by habits researcher extraordinaire Associate Professor Amanda Rebar (who was one of my PhD advisors) shows us just how much of daily life runs on autopilot. Over a week, participants were pinged on their phones and asked what they were doing and whether it felt intentional or automatic. About two-thirds of all actions were triggered by habit, and nearly nine out of ten were performed at least partly on autopilot. So we’re not actively deciding every single tiny thing we do each day: our routines and the influence of our environment mostly quietly guide us through the day.

From these results (and previous work by this research team), one thing gives me hope: when we’re low on willpower, which is typically in the evenings, we tend to fall back on habit even more. So if you go through the initial work to form a healthy habit to support sleep (even just one!), you’re more likely to stick to it when your brain is fried. Your exhausted future self is more likely to follow it without thinking.

So, why are sleep habits so hard to change?

When it comes to sticking to our intentions or trying to change for the better, at night our brains can work against us. Evenings are when our brains seem to be least equipped to change. But once a habit takes hold, that same tired brain can help keep it going.