Don’t Believe Everything You Think

You track your sleep.

You optimise your training.

You care about what you fuel your body with.

But do you audit your thinking?

The human brain produces an estimated 6,000+ thoughts per day. Many are automatic. Many are biased. And many feel true - without being accurate.

Cognitive science has long demonstrated that our minds rely on shortcuts (heuristics) to conserve energy. While efficient, these shortcuts distort reality. Confirmation bias leads us to favour evidence that supports what we already believe (Nickerson, 1998). Negativity bias makes perceived threats more psychologically “sticky” than neutral or positive data (Baumeister et al., 2001). Over time, repeated thoughts become familiar — and familiarity is often misinterpreted as truth.

In Cognitive Behavioural Therapy (CBT), this distinction is foundational: thoughts are mental events, not objective facts (Beck, 1976). A thought like “I’m failing” or “This will go badly” may feel convincing - particularly under stress or sleep deprivation - but emotional intensity is not evidence.

Neuroscience reinforces this. Brain imaging studies show that emotional reasoning and threat perception are amplified when the prefrontal cortex (responsible for rational evaluation) is under strain, such as during fatigue or chronic stress (Arnsten, 2009). In other words, the more overloaded you are, the less reliable your thinking may be.

For high performers, this matters.

Unchecked thoughts influence physiology: stress response, sleep latency, recovery, decision-making, and ultimately performance. When we treat thoughts as facts, we react. When we observe them as mental events, we respond.

The shift is subtle but powerful:

• Instead of “This presentation will be a disaster,” try “I’m having the thought that this might go badly.”

• Instead of “I can’t cope,” try “My mind is predicting I won’t cope.”

This creates cognitive distance - what psychologists call cognitive defusion - reducing emotional reactivity and increasing behavioural flexibility (Hayes et al., 2006).

You wouldn’t believe every headline you read.

Why believe every thought you think?

Reflection:

What thought have you been treating as a fact this week - and what changes if you question it?

References:

Arnsten, A. F. T. (2009). Stress signalling pathways that impair prefrontal cortex structure and function. Nature Reviews Neuroscience, 10(6), 410–422.

Baumeister, R. F., Bratslavsky, E., Finkenauer, C., & Vohs, K. D. (2001). Bad is stronger than good. Review of General Psychology, 5(4), 323–370.

Beck, A. T. (1976). Cognitive Therapy and the Emotional Disorders. International Universities Press.

Hayes, S. C., Luoma, J. B., Bond, F. W., Masuda, A., & Lillis, J. (2006). Acceptance and Commitment Therapy: Model, processes and outcomes. Behaviour Research and Therapy, 44(1), 1–25.

Nickerson, R. S. (1998). Confirmation bias: A ubiquitous phenomenon in many guises. Review of General Psychology, 2(2), 175–220.