Stress and impulse control — why you fall back into old habits when it matters most

Stress and impulse control are linked in a way that makes most of what we believe about willpower wrong. Under stress, you don’t just get more tired — your brain shifts control from what you’re planning to what you’re already used to. That’s why you fall back into old habits just when you needed the new ones most. It doesn’t mean you need to pull yourself together better. It means that what’s needed to cope under stress must be built up when things are calm.

The brain switches drivers under pressure

The part of the brain that plans, weighs up the pros and cons and curbs impulses is located at the very front, in the prefrontal cortex. Neurobiologist Amy Arnsten has summarised the research on how it is affected by stress. Her conclusion: even moderate, short-term stress impairs the prefrontal cortex’s ability to control behaviour, whilst older, more automatic systems in the brain gain greater influence.

From an evolutionary perspective, this makes sense. In a dangerous situation, it is better to react quickly than to think things through at length. The problem is that the brain does not distinguish very well between a predator and a full shopping basket.

From goal to habit

Lars Schwabe and Oliver Wolf conducted an experiment that demonstrates what this means in practice. Test subjects were taught that two different actions resulted in two different rewards. Then one of the rewards became less attractive. A person guided by their goal should then stop performing that action. A person driven by habit, however, carries on regardless.

Those who had previously been exposed to stress were more likely to continue with the habitual action, even though the reward was no longer worth it. They had gone from being driven by what they wanted to being driven by what they were used to doing.

Most of this research has been carried out in laboratories or on animals, and laboratory stress is not the same as a tough week at work. But the pattern matches what most people recognise: on the day when everything goes wrong, it is the old habit that takes over, not the new resolution.

That’s why willpower is the wrong strategy

If stress diminishes the very ability you need to resist, a plan based on resistance is doomed to fail when it matters most. It holds up on calm days but crumbles on the difficult ones — which are precisely the days it was supposed to hold up.

The same applies to sleep deprivation, which affects the brain in a similar way. Anyone who is both stressed and has slept poorly has two forces working against them at the same time — this is described in more detail in the article on sleep deprivation and impulse control. And the reason why self-control, in practice, is less about willpower than about structure is explained in the article on self-control or willpower.

Build your habits when things are calm

If stress causes you to fall back on your old habits, the solution is to ensure that those habits are ones you actually want. This requires practising when you’re feeling energised, so that the behaviour becomes automatic when you’re not.

Practise your new habits on quiet days. Every time you put your phone in the hall on a normal evening, you make it easier to do the same thing on a difficult evening.

Make the good choice the easy choice. When you’re under stress, you’ll take the path that requires the least effort. Make sure that path leads in the right direction: your phone out of reach, no snacks in the cupboard, your computer switched off after work.

Have a plan for a bad day. Write down in advance what you’ll do when things get tough: if I come home completely knackered, I’ll go for a ten-minute walk before sitting down. The plan doesn’t have to be perfect, just decided in advance.

Reduce the stress a little, not completely. A few slow breaths or a short walk can lower the level enough for you to regain some control. It won’t make the stress go away, but it might be enough to make a choice.

When the stress is too much

Temporary stress is part of life. Long-term stress that won’t go away – with sleep problems, persistent anxiety, low mood or physical symptoms – is something else entirely. In that case, impulse control isn’t the problem, and it won’t be solved by better habits. Speak to your GP or occupational health service.

For everyone else, the most important insight is simple: the person you are under stress is the person you have trained yourself to be. How to structure that training is explained in the article on practising impulse control.

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The Zenith Protocol is a 30-day programme for impulse control that builds habits into your daily life, so that they remain in place when things get tough. It’s free to get started.