We all know the feeling of craving an afternoon pick-me-up. Regardless of how much sleep you’ve gotten the night before—afternoon is a time of day when our hormonal and circadian rhythms seem hardwired to take a siesta or power nap. Obviously, for anyone who is chronically sleep deprived, the need for a midday jolt of energy to stay alert and keep chugging along at work or school is going to be more pronounced. Unfortunately, consuming caffeine in the afternoon can create a vicious cycle of making it less likely you'll sleep well that night, which will cause you to crave caffeine the following afternoon...and so on, and so on.
But there is good news: The latest empirical evidence suggests that 10 minutes of walking or climbing a few flights of stairs is actually a more effective way to boost your energy and vigor than consuming 50 milligrams of caffeine.
This first-of-its-kind study on the energizing benefits of small doses of physical activity compared to caffeine was conducted by Patrick O’Connor and Derek Randolph from the Department of Kinesiology (Exercise Science Programs) at the University of Georgia and published in the Journal of Physiology & Behavior.
Randolph and O’Connor were curious to see if a brief bout of exercise or consuming a 50 mg caffeine tablet—which is roughly the equivalent of a can of soda, cup of tea, or shot of espresso—provided more of an energy boost for chronically sleep deprived adults (18-23 years of age) who frequently used caffeine to improve their afternoon alertness.
The researchers state, “The acute energizing effect of exercise and caffeine has never been examined in a single study of adults with chronic sleep deprivation but evidence from a study of this type could help individuals choose between these two common alertness-enhancing options.” More specifically, the researchers found that the energizing effect of 10 minutes of low-to-moderate intensity exercise was greater than 50 mg caffeine for study participants who were sleeping less than 45 hours per week (under 6½ hours per night).
While designing the parameters of this study, O'Connor wanted to simulate typical physical activity hurdles encountered by people who work in an office. The researchers chose stair climbing as a form of physical activity because most office workers have access to a stairwell in which someone can casually slip away from his or her desk and squeeze in a quick workout without needing to change into athletic gear or shower before returning to work. Additionally, in terms of creating a daily habit, taking a quick break from staring at your computer screen to walk some stairs can become an afternoon routine that isn’t dependent on weather conditions.
Although this study doesn’t address sleep hygiene directly, experts agree that consuming caffeine in the afternoon can disrupt evening sleep patterns and exacerbate insomnia. The American Sleep Association (ASA) tip sheet states, “The effects of caffeine may last for several hours after ingestion. Caffeine can fragment sleep, and cause difficulty initiating sleep. If you drink caffeine, use it only before noon. Remember that soda and tea contain caffeine as well.” (Sleep hygiene is defined as, “habits and practices that are conducive to sleeping well on a regular basis and having full daytime alertness.”)
The win-win of taking an afternoon walk or climbing some stairs to boost energy instead of reaching for a caffeinated beverage is that low-to-moderate intensity exercise will improve your physical and psychological well-being in the short and long term, as well as help you sleep better at night.
If you are experiencing an afternoon energy lull as you read this, remember: Substituting a 10-minute dose of low-to-moderate intensity exercise instead of an afternoon shot of caffeine is the perfect midday energizer. Brief bouts of exercise can help break the vicious cycle of caffeine-induced sleep deprivation while countering the overall detriments of sedentarism and sitting too much during the day.
Derek D. Randolph, Patrick J. O'Connor. Stair walking is more energizing than low dose caffeine in sleep deprived young women, Physiology & Behavior (2017). DOI: 10.1016/j.physbeh.2017.03.013