Between one siren and the next, many of us find ourselves performing an almost automatic action: Preparing another cup of coffee. But precisely in moments of tension and anxiety a less intuitive question arises – does coffee really help cope with stress, or does it actually add another layer of alertness to a body that is already in an emergency state?
Before the first cup of the morning, the body, which spent most of the night in a state of alert, is already secreting cortisol – one of the central hormones that mediate the body's response to stress. The coffee that arrives afterward does not enter a neutral environment, but meets a hormonal system that is already on edge. Caffeine is one of the substances that act on the central nervous system, and one of the most consumed in the world. Its effect on alertness is well known. However, in prolonged stress situations, like those experienced by many in Israel in the recent period, the combination of tension and caffeine may act in several different directions.
Why does the body not always react in the same way?
When we are under chronic stress, the body activates its hormonal "emergency system" more often, a system whose role is to increase alertness and energy in order to cope with load. In such a state the system may be more "on edge" and calm down more slowly.
When caffeine enters the picture, it blocks fatigue signals in the brain and increases alertness. In controlled studies it has also been found that it can raise cortisol levels and intensify the stress response, especially among those who are not regular coffee drinkers and at higher doses than usual. This may be expressed in a faster pulse, restlessness and a feeling that the cup that was meant to help – actually increases tension or anxiety. However, the picture is not unequivocal, and among regular coffee consumers there is sometimes adaptation, so the hormonal response weakens, and in certain situations the improvement in alertness and functioning may even be perceived as easing the sense of load.
Therefore the question of what happens when coffee is added to a state of chronic stress does not receive one answer. The result depends on the dose, drinking habits and personal sensitivity to caffeine. And this is exactly the reason why the scientific literature describes worsening among some people, and a neutral or even beneficial effect among others.
Not only how much you drink – but also when
A large study based on data from the American NHANES survey and published in 2025 in "European Heart Journal" compared two drinking patterns: People who drink most of their coffee in the morning versus those who drink coffee throughout the day. The researchers found that drinking coffee mainly in the morning was associated with a lower risk of overall mortality and mortality from heart disease. However, this is an observational study and therefore it indicates only a statistical association and does not prove cause and effect. But the study does raise another practical question: What happens when coffee is pushed to later hours of the day – hours in which it may interfere with sleep and the biological clock, two central factors that influence health.
And this is a particularly important point for these days, when anxiety and repeated awakenings to reach the protected spaces interfere with continuous sleep. A cup of coffee at 18:00 can give the feeling that it is "exactly what is needed", but in the context of sleep there is a finding that appears again and again in studies and in sleep hygiene recommendations: Caffeine consumed even six hours before bedtime can impair sleep measures, including sleep duration. Therefore, if you identify that sleep is being affected: Difficulty falling asleep, fragmented sleep or early awakening, it is recommended to try to drink coffee earlier, switch to decaffeinated coffee in the afternoon hours or choose another beverage.
One myth worth debunking
There is no medical recommendation to start drinking coffee, but in terms of safety leading health bodies in the world indicate a general consumption limit for caffeine. The European Food Safety Authority (EFSA – European Food Safety Authority) and the U.S. Food and Drug Administration (FDA – Food and Drug Administration) note that consumption of up to about 400 mg of caffeine per day from all sources is considered safe for most healthy adults. In practice this amounts to three to four average cups of coffee, although the caffeine content can vary greatly depending on the type of coffee, the preparation method and the size of the cup.
However, during periods of stress and anxiety, or among people who are sensitive to caffeine, even a smaller amount may cause symptoms such as nervousness, trembling, rapid pulse or difficulty falling asleep. In such cases it may be worthwhile to reduce coffee consumption, make do with one small cup, switch to decaffeinated coffee or choose another beverage, such as green tea or an herbal infusion.
Beyond caffeine, coffee also contains additional active compounds, including polyphenols – substances that are attributed with antioxidant activity, activity that protects the cells and slows their aging. Because of its high consumption, coffee is considered in the Western diet one of the main sources of antioxidants. During the roasting of the beans some of these compounds change, and at the same time new substances are formed from the natural browning process of coffee, including melanoidins, which are also attributed with antioxidant activity. Therefore dark roasting is not necessarily "better" or "worse", it simply changes the chemical composition of the beverage.
Another common myth is that coffee "dehydrates". Caffeine may indeed increase urination, mainly among those who are not used to drinking coffee. However, in controlled studies conducted among regular coffee drinkers no difference was found in hydration measures – that is, measures that express the fluid status in the body – between drinking coffee and drinking water when consumption was moderate.
Coffee is neither an enemy of health nor a miracle cure. For most people it can be part of a balanced diet, as long as it is consumed in moderation and at hours that suit the body. Precisely during periods of tension and fatigue, it is worth paying attention not only to the number of cups of coffee but also to the hour at which they are consumed. Sometimes the difference between coffee that helps and coffee that interferes simply begins with timing.