A meta-analysis of 48 studies published in Nutrients has quantified caffeine’s ergogenic effect: doses of 3–6 mg per kilogram of body weight, taken 45–60 minutes before exercise, improved endurance times by more than 2% on average across cycling, running and swimming trials. The mechanism is well established—caffeine temporarily blocks adenosine receptors in the brain, delaying the perception of fatigue. Yet the same neurochemistry explains the subsequent crash. A Russian dietitian describes a “coffee rollback” syndrome, occurring four to five hours after consumption, when adenosine floods back and alertness drops sharply. The speed of that decline depends on individual metabolism, with fast metabolisers feeling the slump within two hours and slow metabolisers up to ten hours later, while some notice no fall at all.

A separate, large observational study from the UK Biobank, tracking 354,957 participants over a median of 13 years, reports that regular coffee drinking is associated with a markedly lower risk of liver disease. Compared with non-drinkers, those consuming five or more cups a day had a 32% lower risk of cirrhosis, a 47% lower risk of liver cancer, and a 42% lower risk of death from liver disease. The association was already visible at one to two cups daily and was strongest at three to four cups. MRI scans and blood markers showed less liver fat, inflammation, fibrosis and iron accumulation in coffee drinkers, offering a possible biological pathway. The authors, writing in Clinical Gastroenterology and Hepatology, stress that the findings do not prove causation and that coffee should complement, not replace, weight control, alcohol limitation and metabolic monitoring.

Viewed from Argentina, this dual nature of caffeine—a short-term performance tool that can deepen later fatigue—intersects with what specialists at the National University of La Plata call an “era of tiredness.” Hyperconnectivity, the blurring of work-life boundaries and the pressure to remain perpetually available have turned exhaustion from an occasional signal to rest into a chronic state, they argue. The burden falls disproportionately on women, who often combine paid employment with caregiving. In this context, caffeine becomes a daily crutch, masking but not resolving an underlying deficit. At the extreme end of sleepiness disorders, US-based sleep specialists describe narcolepsy, a neurological condition affecting roughly one in 2,000 people, characterised by sudden sleep attacks and cataplexy; for the wider population, however, the problem is less a brain disorder than a lifestyle-driven accumulation of fatigue.

Practical guidance from Southeast Asian health sources emphasises hydration, short movement breaks and 10–20-minute power naps to counter daytime sleepiness, while the sports-nutrition review recommends starting with low caffeine doses near 200 mg for a 70 kg person and adjusting according to individual response. The Russian dietitian notes that withdrawal symptoms—headache, fatigue, difficulty concentrating—peak within the first 48 hours of stopping caffeine and can last up to nine days, with those consuming more than 300 mg daily at greatest risk. The Argentine researchers add that the time and attention consumed by digital devices themselves erode the very rest that caffeine is meant to compensate for.

What comes next is a push to move from association to intervention. Randomised controlled trials are needed to test whether coffee’s liver-protective signals are causal, while occupational health researchers are beginning to frame hyperconnectivity as a modifiable risk factor for chronic fatigue. For now, the evidence suggests that caffeine can sharpen performance and may confer long-term organ-specific benefits, but its tactical use must be weighed against the strategic cost of a society that rarely switches off.