Caffeine in coffee has been shown to promote mental alertness and improve stamina in high performance athletes.
‘When you have your espresso ‘pick me up’, you are feeling the stimulating effect of caffeine, which activates noradrenalin neurons, nerve cells in the central nervous system, triggering the body’s ‘fight or flight’ response,’ explains Steve Bazire, professor of pharmacy practice at the University of East Anglia and a member of the College of Mental Health pharmacists. ‘This temporarily elevates blood pressure and heart rate, which makes you feel more alert because more oxygenated blood is pumping around the body.’ Effects can last for hours, depending on tolerance levels. The half life of caffeine is 5-6 hours, meaning it can take 24 hours for it to be passed out of the body. Caffeine also stimulates the release of ‘feel good’ dopamine, which activates the pleasure centres of the brain, although the effects are temporary only.
However, don’t rely on caffeine as a pick-me-up longterm as studies have shown that people who regularly drink coffee to remain alert become tolerant to caffeine so they are no more alert after drinking it than non-coffee drinkers in the long term.