Chronic lack of sleep makes it hard to focus on a task. As if this didn’t make complete logical sense, multiple research studies have shown that sleep deprivation has about the same effect on our cognition and coordination as a few alcoholic beverages.
What do you do when you need to concentrate, but you’re tired?
Many of us reach for a cup of coffee, or a soda. Mountains of solid research have shown us that caffeine (in doses ranging between 30 and 300 milligrams) improves attention, alertness, reaction time, and mood, especially when we’re tired. An average cup of brewed coffee contains between 80 and 100 milligrams of caffeine; a soda, between 30 and 60.
But exercise works too. This is also well-studied. Even a short bout of any cardiovascular exercise wakes us up, speeds mental processes, and enhances memory storage and retrieval, regardless of our fitness or fatigue levels.
So, when it’s late afternoon and I’m struggling with charting or finishing one of these pieces, what should I do: exercise a bit, or go for coffee?
One recent (and very small) study compared these two wake-up methods. This well-conducted study used healthy but chronically sleep-deprived volunteers to compare three interventions: caffeine, stair-climbing, and placebo. They found that just 10 minutes of stair-climbing boosted self-reported levels of energy far more than a moderate dose of caffeine (50 mg). However, this was a very small study — only 18 out of 90 healthy, college-aged women met all the criteria and were willing to participate.
Digging deeper: Exercise offers more long-term benefits
While the findings make a whole lot of sense, I went to the existing piles of literature for more information.
Interestingly, another study looked at the effects of either exercise alone or exercise plus caffeine on cognitive tasks, and found that (perhaps predictably) exercise plus caffeine had the greater benefit.
Caffeine (in the form of coffee) has been well-studied, and regular intake is associated with lower risk of type 2 diabetes, high blood pressure, and obesity, but may increase cholesterol. It may be protective against certain types of dementia and cancer, but has been associated with bone loss and rheumatoid arthritis. Basically, there are many benefits, but there seem to be some risks as well.
But there are multiple studies suggesting that exercise has multiple long-lasting positive effects on physical fitness and function, cognition, mood, and behavior in just about all populations studied, in all ages, fitness levels, and regardless of baseline cognitive function. Some of the greatest benefits have been seen in older patients, as well as patients at risk for or diagnosed with dementia.
The take-home message? Caffeine can provide a boost in alertness and energy levels that may help you to think faster and better, for a while. But even a short burst of exercise can do the same, maybe more, and for longer. In addition, while caffeine is associated with both good and bad health outcomes, exercise is good for everything.
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Moderate sleep deprivation produces impairments in cognitive and motor performance equivalent to legally prescribed levels of alcohol intoxication. Occupational and Environmental Medicine, 2000.
Fatigue-related impairment in the speed, accuracy and variability of psychomotor performance: comparison with blood alcohol levels. Journal of Sleep Research, 2005.
A review of caffeine’s effects on cognitive, physical and occupational performance. Neuroscience & Biobehavioral Reviews, December 2016.
Diet, Brain, Behavior: Practical Implications, CRC Press, 2011.
The effects of low doses of caffeine on human performance and mood. Psychopharmacology, 1987.
Is caffeine a cognitive enhancer? Journal of Alzheimer’s Disease, 2010.
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Coffee and autoimmunity: More than a mere hot beverage! Autoimmunity Reviews, May 2017.
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