Coffee at night can make women impulsive, study finds

Drinking coffee at bedtime can make women engage in impulsive behaviour, a new study has found out.

Some scholars at the University of Texas at El Paso have found consuming caffeine in late evening hours was causing female flies to engage in risky or uncontrollable behaviour.

The researchers also found that the effects of caffeine were changing between day time drinking and night consumption.

The study highlighted the findings had greater implications on people who rely on caffeine at night, including shift workers, healthcare professionals and military personnel.

What did the study find?

Led by Eric Saldes, the team at the University at Texas wanted to study the effects of caffeine on Drosophila melanogaster, a species of flies commonly used for experiments because of its genetic and neural similarities to human beings.

The team fed these flies with caffeine under different conditions such as: caffeine at day time, caffeine during evening hours, caffeine with sleep deprivation and caffeine without sleep deprivation.

They aimed at evaluating impulsivity in flies by observing if they could effectively stop when exposed to a strong airflow, something flies inherently find unpleasant.

Under normal circumstances, flies stop when exposed to strong winds, the lead scientist had informed.

To their surprise, the scientists found those flies behaving differently on consuming caffeine. Flies, which were fed caffeine at night were less likely to suppress movement on exposure to the wind, engaging in risky behaviour and reckless flying.

The study found that caffeine at night disrupted the motor responses in the flies, and this reckless flying was not linked to sleep deprivation or hyperactivity.

Flies with impaired inhibitory control showed rapid movements at speeds exceeding 60mm/s.

The same flies responded differently to caffeine during the daytime, suggesting a link between the circadian cycle (sleep-wake cycle in humans) and caffeine metabolism.

This was found similar to how caffeine affects human behaviour, increasing daytime alertness and during evening hours disrupting the sleep cycle. 

Women more prone to be affected

The researchers observed some differences in the sexes, male and female flies behaving differently to the same amount of caffeine in their systems.

The study found that female flies displayed higher levels of impulsive behaviour in comparison to male flies.

Because of the systemic similarities between the flies and humans, scientists assume a similar response can be observed in human females.

Scientists argued the flies had no hormone-driven systems that could heighten the impulsivity so there must be other physiological causes increasing impulsive behaviour in women.

Notably, high caffeine consumption in children, adolescents and young adults have been linked to greater sensation-seeking and risk-taking tendencies.

As per a study, caffeine consumption was also associated with early onset of gambling and nicotine co-use among gamblers.