Myth 2: It’s best to wait 90 minutes after waking before having coffee

This advice, popularised by wellness podcasters, claims that drinking coffee straight after waking clashes with the body’s natural morning cortisol peak and leads to an afternoon energy crash.

Cortisol does rise naturally soon after waking, and caffeine can increase cortisol. However, research shows that in regular coffee drinkers, this cortisol response is largely blunted by tolerance, and there
are no studies showing that a 90 to 120-minute delay improves energy levels or prevents an afternoon slump.

Interestingly, a large US study of more than 40,000 adults found that people who drank their coffee mainly in the morning had a 16 per cent lower risk of death from any cause and a 31 per cent lower risk of death from cardiovascular disease compared with non-drinkers. People who drank coffee throughout the day did not show the same benefit. However, this was also an observational study, so it cannot prove cause and effect.

The timing advice with the strongest evidence is about the other end of the day: that caffeine taken even six hours before bed can significantly disrupt sleep.

The verdict: There is no need to delay the first cup of the day. A cut-off time in the afternoon is far more important than a start time in the morning.