Daijiworld Media Network - Mumbai

Mumbai, Apr 2: A growing body of research is shedding new light on the effects of caffeine, suggesting that drinking coffee late at night may do more than just disrupt sleep. According to a recent study published in iScience, nighttime caffeine consumption could increase impulsive behaviour, particularly among women.

For years, experts have linked caffeine intake to sleep disturbances, as it blocks adenosine — a brain chemical responsible for promoting sleep — thereby interfering with the body’s natural sleep-wake cycle. However, this new research points to a deeper impact on behavioural control and decision-making.

Researchers from University of Texas at El Paso conducted experiments using Drosophila melanogaster, a commonly used model for studying neurological processes. They found that subjects exposed to caffeine at night showed reduced ability to suppress reactions to negative stimuli — a sign of increased impulsivity.

Interestingly, the same effect was not observed when caffeine was consumed during the day, highlighting the importance of timing.

The study also found that female subjects displayed a stronger increase in impulsive behaviour compared to males. Scientists suggest this may be due to biological differences in how caffeine is metabolised and how brain chemistry responds, an observation supported by previous research in the field of nutrition and neuroscience.

Caffeine stimulates the central nervous system by blocking adenosine receptors and increasing the release of neurotransmitters like dopamine and norepinephrine. While this boosts alertness, excessive stimulation — especially at night — can disrupt circadian rhythms and impair functions like judgement, emotional control, and focus.

Studies have shown that consuming caffeine within six hours of bedtime can significantly reduce sleep quality, which in turn affects cognitive performance the next day.

What makes these findings notable is the shift from sleep-related concerns to behavioural consequences. Increased impulsivity is linked to risk-taking behaviours, including poor decision-making, emotional instability, and reduced self-control.

Experts caution that late-night caffeine consumption could subtly influence such behaviours, especially in high-pressure lifestyles where individuals rely heavily on coffee to stay awake.
In a fast-paced world where late-night work is common, many people depend on caffeine for productivity. However, organisations like the Mayo Clinic warn that excessive or poorly timed caffeine intake can lead to insomnia, anxiety, restlessness, and increased heart rate.

Over time, this can create a cycle of poor sleep and higher caffeine dependence, potentially affecting both health and behaviour.

While more human-based studies are needed, the findings highlight an important takeaway: the timing of coffee consumption matters. Limiting caffeine intake to earlier in the day may not only improve sleep quality but also help maintain better emotional balance and decision-making ability.