When I wake up, before I even think about the day ahead of me, before I feel the need to get my cellphone fix (more on that later), the first thing that comes to mind is coffee. LIke zombies looking for braaaaaaaains, I want my coooooooffee.
This craving is no accident. We love our caffeine. No, this is not the same as addiction, but yes, caffeine can be habit forming. It’s estimated that 90% of the world’s population uses caffeine in one form or another. Coffee and tea are for sure the major sources of caffeine for adults. Soft drinks contribute a significant amount of caffeine for children and adolescents; and with the introduction of energy drinks, caffeine consumption in this younger age group is higher than ever before.
Caffeine, whether it’s from coffee, tea, cola-based soft drinks or Mountain Dew, energy drinks or even to a lesser extend chocolate, is a ‘psychotropic’ compound – defined as anything ‘affecting mental activity, behaviour or perception, as a mood-altering drug’. On that note, time to put the coffee maker on, I’ll be right back.
Your brain on caffeine
Your brain and spinal cord are referred to as the central nervous system or CNS. Under normal conditions, levels of a chemical called adenosine rise each hour throughout the day which helps to promote sleep and suppress arousal by slowing down nerve activity. Caffeine helps to alleviate fatigue by blocking the action of adenosine in the brain.
With caffeine blocking adenosine, there is an increase in the levels of both excitatory and feel-good neurotransmitters such as norepinepherine or nor-adrenaline which gives a sense of increased wakefulness and alertness. Studies show improved task performance with modest intakes of caffeine, in the 200 to 400 mg range, because of caffeine’s ability to increase mental alertness, thought-processing speed, performance, reasoning and memory. It’s no wonder we love a bit of caffeine in the morning to get the ‘cobwebs’ out.
Caffeine also increases the production and release of the neurotransmitters dopamine and serotonin; two neurotransmitters that are associated with increased attention, focus and well-being & pleasure. This is one of the ways caffeine can modestly improve mood (note: norepinepherine also has mood-enhancing properties too). We feel alert, able to focus with a sense of pleasure, our outlook tends to be better. Some research has even shown that consumption of modest amounts of caffeine is protective against depression for this very reason.
It’s caffeine’s dopamine/serotonin-raising properties that brings that feeling of ‘aaahhhhh’ with the first few sips, not until the reward we all get for checking our cellphones and finding a text or email.
Too much of a good thing?
Like with anything in life, there is ALWAYS a Goldilocks zone; the sweet spot where it’s not too cold/bad and not too hot/bad but rather ‘just right’. While research supports caffeine’s role in improving mood, performance and fighting fatigue with intakes in the 200 mg to 400 mg per day range [give or take], it is possible to get too much of a good thing.
With too much caffeine, the body will over-produce stress hormones like cortisol, as well as, adrenaline/norepinepherine. While small amounts are OK, too much will shift your body into a state of emergency or ‘fight or flight’. Adrenaline is famous for that shakiness, irritability and agitation that comes when were super pissed off with someone, super stressed out or after a big blowout. When too much caffeine is consumed, i.e. 600 mg 800 mg or 1000 mg or more, you can experience symptoms indistinguishable from anxiety disorders, general agitation, anger, stress and irritability. Your CNS reacts the same resulting in the same negative effects on your whole body.
As well, with the ‘crash’ that comes after the caffeine rush, it’s possible to experience rebound depression as levels of dopamine, serotonin and norepinephrine levels plummet. For those without any mental health issues in the way of anxiety disorders, depression, bipolar disorder or whose emotions are otherwise not labile/heightened due to situational stresses, this crash isn’t likely to be a problem but for anyone else, it will be. Working in mental health and addictions, it’s not uncommon for me to see patients consume 1500+ mg of caffeine per day; the effects of this much caffeine aren’t pretty.
Caffeine peaks in the bloodstream about 45 minutes after consuming it and it takes your liver about 5 hours to breakdown about half, or 50% of what’s be consumed. It’s for this reason that heavy consumers of caffeine are in effect perpetually ‘caffeinated’. Even though people report being able to sleep, and they do, caffeine can interfere with the normal sleep cycle: people will not go into restorative sleep as often throughout the night nor stay in that sleep cycle as long. It’s effects are subtle but real; sleep quality is impacted and poor sleep is now recognized as a risk factor for chronic illness (morbidity).
Caffeine intake guidelines & sources
- For women of childbearing age: no more than 300 mg caffeine/day.
- For healthy adults: no more than 400 mg caffeine/day.
- Age 12 and under: no more than 2.5 milligrams of caffeine per kilogram of body weight
- Age 4-6: 45 mg/day
- Age 7-9: 62.5 mg/day
- Age 10-12: 85 mg/day
Sources of caffeine
Average caffeine content [Canadian Nutrient File]
- 1 cup [250 ml or 8 oz] of brewed coffee = 125 – 175 mg
- 1 cup [250 ml or 8 oz] of instant coffee = 76 – 106 mg
- 1 cup [250 ml or 8 oz] of brewed tea = 45 – 80 mg
- 1 cup [250 ml or 8 oz] of cappuccino or latte = 45 – 75 mg
- 1 cup [250 ml or 8 oz] of green tea = 30 mg
- 1 cup [250 ml or 8 oz] decaffeinated coffee = 3 – 5 mg
- 1 can [355 ml or 12 oz] cola = 45 mg
- 1 oz [30 ml ] espresso = 50 – 80 mg
- 1 cup [250 ml or 8 oz] chocolate milk =
- Red bull [250 ml or 8 oz] = 80 mg
- Energy drinks such as Monster [500 ml or 16 oz] = 230 mg
- Chocolate, dark 1 bar (40 g) = 30 mg
- Chocolate, milk 1 bar (40 g) = 2 -12 mg
- Coffee beans, chocolate covered dark or milk 1/4 [60 ml] = 338 – 355 mg
- Caffeine is a commonly consumed compound. 90% of the world’s population consumes caffeine in one form or another every day
- Modest amounts of caffeine, 200 mg to 400 mg per day, have not been shown to cause any health problems
- People’s sensitivity to caffeine varies so listen to your body and don’t over do it
- Caffeine can improve some aspects of daily life such as increased alertness, memory, reasoning, and performance of simple tasks
- Caffeine can improve mood and feelings of well-being via it’s ability to very modestly raise levels of the neurotransmitters norepinepherine, dopamine & serotonin
- Consuming more than 500 mg to 600 mg of caffeine per day can lead to problems such as irritability, anxiety, muscle tremors, headaches, and disrupted sleep cycles
- Caffeine is present in many foods, beverages and even medications: be sure to consider all sources when estimating your caffeine intake.
- You can confidently enjoy your favourite cup, or two, or tree [depending on the size] of joe: espresso, latte, cappuccino, Americano every day!