For many Australians, morning means coffee and a shot of the good stuff is a key part of their daily routine.
But while thousands of people rely on that first coffee to help them hit their work day running, they may be better placed to wait a few hours to get the best pick-me-up results from their caffeine.
Our body's production of cortisol – the hormone playing a major role in regulating our sleep/wake cycle, among other things – tends to peak first thing in the morning.
"With cortisol, in a sense, your body has got its own internal coffee production line," explains Professor Bernard Champion, from Macquarie's Department of Clinical Medicine.
"Most people who drink coffee experience a relatively rapid (within 20 minutes) boost similar to a surge in cortisol production, as both caffeine and cortisol act on the sympathetic nervous system, stimulating the production and actions of neurotransmitters such as adrenaline."
Champion is used to dealing with patients who struggle to manage alertness. As an endocrinologist, he focuses on the medical conditions related to any imbalances with the 200-plus hormones in the human body and many of these impact on our sleep.
When our hormones work properly, the levels of cortisol rise and fall over a 24-hour period, with cortisol production tending to rise from 5am to peak around 8am and lowest around the midnight-3am period, Champion explains.
Societal structures mean that few people follow the natural rhythms of rising with the sun and going to sleep shortly after nightfall – but our hormone levels tend to still reflect this long-term adaptation, he says.
The effects of caffeine occur naturally in the morning, so delaying your daily coffee consumption till mid-late morning could mean you give your body an energy boost when you really need it, as your cortisol levels off.
"We tend to look at drugs like tobacco and alcohol more critically than things like tea and coffee because they are more likely to cause health problems," Champion says.
"But I've had patients with very high caffeine consumption, often from energy drinks for example, who essentially were taking the equivalent of about 20 cups of coffee a day and not surprisingly they find they have trouble with insomnia, anxiety and cardiac issues such as palpitations."
Caffeine overuse can make hormone symptoms worse
Champion says that our bodies can become accustomed to caffeine and over time (the process known as "tolerance"), you may need more to get the same effect. "It's the same principle with the way that opiates act on our receptors – there's a degree of reduced sensitivity to the effects and you have to keep increasing the input to get the same result," he says.
"We know that the effect of caffeine comes on over about 30 minutes and can last up to six hours, so managing the time of your caffeine consumption, as well as the amount, is just common sense."
The symptoms of caffeine overuse can sometimes mimic various endocrine disorders, he adds.
"We do screen our patients to find out how much coffee they drink, for example, because it can exacerbate symptoms of other hormone imbalances, for example overactivity of the thyroid or adrenal glands."
Champion says that it's important to remember that different people will vary in their sensitivities to the effects of caffeine.
Overuse of caffeine can cause heart palpitations, insomnia and anxiety in some, he says, but in moderation there's no definitive links between moderate consumption of coffee and ill health.
"Most studies show that caffeine has no ill effects and there are some studies suggesting some health benefits of moderate consumption," he says. "It clearly has some positive effects on things around mood, memory, mental sharpness and cognitive function – but like most things, too much of it either becomes ineffective or deleterious."
This article was first published on the Macquarie University Lighthouse.