Not a day goes by that you don’t see someone with a coffee cup in their hands, sipping away.

Coffee is a hot topic, so it’s no wonder that it’s widely researched. Moderate consumption is generally considered to be three to five cups a day (equivalent to 400mg of caffeine) and research shows that it contributes favourably to our health. For example, caffeine and phytochemicals have been shown to boost alertness, concentration and performance in many cognitive tasks.

If you’re an athlete, research has also shown that caffeine can be a powerful ergogenic aid – it can improve performance during endurance, high-intensity and resistance exercise. Interestingly, it was banned by WADA until 2004 and is now on the monitoring list.

However, does this mean that everyone should be consuming three to five cups of coffee per day?

The key to how much depends on the individual and their genetics. Those of us who are not genetically suited to processing caffeine (‘slow metabolisers’) should minimise/avoid caffeine or opt for decaf instead. Recent research shows that athletes in this group can actually hinder their performance if they ingest too much caffeine before a race. But if you are genetically suited to processing caffeine, you can drink coffee: three to five cups is the average recommendation. But we still need to be prudent.

Caffeine is a powerful stimulant that increases the production of stress hormones, such as cortisol. Cortisol affects the HPA (hypothalamic-pituitary-adrenal) axis that links the hypothalamus and pituitary gland in our brain and the adrenal glands on top of our kidneys. This system is known to regulate our hormonal stress response.

If you’re consuming three to five cups a day and are feeling relaxed, this increase in cortisol has a short-term effect and is not really a problem. But if you’re consuming three to five cups a day on top of other stressors in your life (e.g. lack of sleep, stress with work, high training volume), this might well be stressing the HPA axis and jeopardising your health. You feel drained/fatigued and anxious, have a low sex-drive, possibly gain weight and are more likely to develop an infection or illness.

Drinking too much coffee and/or consuming it later in the day can also affect the quality of your sleep because it blocks the adenosine receptors in your brain (adenosine makes you feel relaxed and sleepy). In turn, this lack of sleep is just another stressor on the HPA axis.

Caffeine has also been shown to inhibit the uptake of iron and B vitamins from food, that are essential for red blood cell production and many other vital bodily functions. That’s why I tell my clients to drink coffee away from meals. That said, coffee on an empty stomach can potentially make you jittery!

Anyone who knows me, knows that I was an avid coffee drinker. I would easily drink up to five black coffees a day. I thought it was helping me stay alert for studying and training, but it was actually making things worse by making me feel more lethargic and irritable. I also wasn’t drinking enough water to hydrate myself because I was drinking so much coffee. One day I decided to switch to one to two cups of decaf – I had a hard time with the withdrawal symptoms, but it was totally worth it for me in the end, as I regained a new sense of energy and calmness.

One word of caution: if you decide to go decaf, make sure you choose a good-quality and chemical-free option. Many decaf options use chemical solvents when extracting caffeine from raw unroasted beans. Your best choice is chemical-free, water-filtered decaf – this method is almost exclusively used for decaffeination of organic coffee.

So, think about your coffee-drinking habits – if you feel drained when drinking coffee, try reducing the amount you’re consuming, or eliminate it completely. If you feel okay with the amount you’re drinking, then it’s fine, and probably even beneficial.

The right amount of coffee boils down to you!