2026.07.15 – Dr Karl Kruszelnicki – Wednesday’s with Dr Karl
1) Wired But Tired
How can you be simultaneously tired yet wired – the paradoxical feeling of being physically exhausted but mentally unable to switch off? Blame your stone‑age brain.
Your “human stress response” evolved to respond to short-term immediate threats (such as a lion) – not to an overflowing email inbox.
When the brain detects threat, a region called the amygdala initiates the body’s classic fight-or-flight response. Stress hormones including adrenaline and cortisol are released. Heart rate increases, breathing quickens and attention sharpens. Energy is diverted away from…
The skinny
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