New Research Indicates Morning Caffeine Enhances Mood

Recent studies indicate that caffeine intake is linked to a notable positive impact, particularly strong within the initial 2.5 hours after waking up (i.e., in the morning).

Individuals who regularly consume caffeine often report feeling better after having coffee or other caffeinated beverages. This effect is noticeable until late morning. Image credit: Sci.News.

“Caffeine is a stimulant for the central nervous system utilized by approximately 80% of the global population and is available in various forms, including coffee, tea, sodas (like Coke), and chocolate.”

“Positive expectations surrounding caffeine use include alleviating fatigue, enhancing cognitive and physical performance, and promoting favorable mood changes.”

“There is a notable gap in research regarding the beneficial effects associated with caffeine in real-world circumstances, especially concerning mood and emotional states.”

The study involved 236 young adults from Germany over a duration of up to four weeks.

Participants answered a brief smartphone survey seven times daily.

This research aimed to explore caffeine consumption in both daily life and controlled laboratory scenarios.

The researchers also examined whether coffee affects individuals differently.

“We were somewhat surprised to find no significant differences among individuals with varying caffeine consumption levels, depressive symptoms, anxiety, or sleep issues,” remarked Dr. Hayenberger.

“The relationship between caffeine intake and emotional responses was largely consistent across all demographics.”

“We anticipated that individuals with higher anxiety levels would experience a decline in mood, including increased tension, after consuming caffeine.”

“However, those who have adverse reactions to caffeine may avoid it, and our study did not include participants who completely abstain from caffeine.”

Scientific findings explain the mood-boosting effects of caffeine on morning emotions, attributed to its ability to block adenosine receptors.

“Caffeine functions by inhibiting adenosine receptors, which can enhance dopamine activity in key brain regions; this phenomenon is linked to improved mood and increased alertness,” states Professor Anu Learro from Warwick University.

“Nonetheless, it’s still uncertain whether these effects are related to diminished withdrawal symptoms following a night’s sleep.”

“Even moderately caffeinated individuals might encounter mild withdrawal symptoms that resolve after their first coffee or tea in the morning.”

study will be published in the journal Scientific Reports.

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J. Haschenberger et al. 2025. Positive effects of association with caffeine consumption do not involve any negative effects changes throughout the day. Sci Rep 15, 28536; doi:10.1038/s41598-025-14317-0

Source: www.sci.news

Can Soil Microorganisms Alter Brain Chemistry and Enhance Mood?

Is soil truly an antidepressant?

Cavan’s Image/Aramie

Numerous intriguing claims about gardening have circulated, especially one that insists, “The soil acts as an antidepressant.”

According to this notion, it’s been promoted through countless social media posts. Mycobacterium vaccae, microorganisms commonly found in soil, are said to improve your mood. Simply engaging with the earth can yield these benefits. It’s believed that these bacteria can be absorbed through your skin or inhaled, subsequently enhancing your brain chemistry. But is this as credible as it seems?

While these claims may appear peculiar at first glance, studies have indeed explored the effects of this microorganism on various health conditions, such as eczema and cancer. Interestingly, M. vaccae was first identified in Ugandan soil samples while scientists sought a non-lethal relative of Mycobacterium tuberculosis, and it has potential as a form of immunotherapy.

Researchers became intrigued by its possible benefits for depression when lung cancer patients treated with this bacteria reported improvements in their quality of life, which was an unexpected yet welcomed side effect. Current research, likely indicating an uplift in mood, has been replicated across numerous well-designed studies. Thus, the internet is rife with memes about this finding.

However, there is a caveat. All studies specifically examining this hypothesis have been conducted on mice rather than humans, which is significant because the outcomes of animal studies are often difficult to extrapolate to humans. For instance, one review of 76 animal studies found that only 37% were replicated in human trials.

Moreover, the mice used in the M. vaccae studies were male and from specific inbred strains. Researchers varied their methods for administering the bacteria, either by saturating the air in their cages or applying it directly to their skin. Most studies I found involved injecting the bacteria into the bloodstream of the mice or incorporating it into their food.

As someone captivated by the growing evidence that suggests spending time in green spaces improves mental health, I eagerly anticipate further research on M. vaccae. Nevertheless, despite the viral nature of the claim that “soil is an antidepressant,” it’s essential to acknowledge that it primarily stems from studies on male mice injected with purified bacteria.

James Wong is a botanist and science writer with a particular focus on food crops, conservation, and the environment. He trained at the Royal Botanic Garden in Kew, London, and shares a small flat with over 500 houseplants. Follow him on X and Instagram @BotanyGeek

For more projects, please visit newscientist.com/maker

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Source: www.newscientist.com