Study Finds Coffee Drinkers Take More Steps, But Get Less Sleep
New research has found that coffee drinkers take more steps, and also get less sleep, than individuals who do not drink coffee each day.
While there have been many claims about how coffee can benefit and negatively affect people’s health, a small study published in the New England Journal of Medicine suggests there are both upsides and downsides to consuming your favorite cappuccino or latte.2
Researchers found people who drink coffee regularly end up taking more steps on average, specifically 1,000 extra steps a day compared to those who do not drink coffee. On the other hand, the study showed coffee lovers lost out on about 36 minutes of sleep on nights when they drank coffee—and the more coffee they consumed, the more sleep they lost.1
“Much of our findings should be considered reassuring. Our data reveal complex and variable effects, which themselves are heterogeneous from individual to individual,” Gregory Marcus, MD, lead author of the study and a professor of medicine in the Division of Cardiology at the University of California, San Francisco, told Health in an email.
“My hope is that people will utilize this information to tailor their own coffee consumption to best fit their own propensities and health goals.”
Coffee Consumption’s Impact on Overall Health
To better understand the immediate health effects of consuming coffee, Marcus and his colleagues recruited 100 healthy men and women from the San Francisco area who were on average about 39 years old.
The participants wore Fitbits that tracked their steps and sleep, a continuous glucose monitor that tracked blood sugar levels along with electrocardiogram (ECG) devices that followed their heart rhythms. All participants were randomly assigned to drink as much coffee as they wanted for two days and then abstain from caffeine for two days. These assignments continued for two weeks, but, none of the participants consumed or abstained from coffee for more than two days.
The researchers found when participants consumed coffee, they got an average of 1,058 more steps than they did on the days they did not drink any coffee. But on those days, they also took a hit to their sleep and lost about 36 minutes of their bedtime.1
Dr. Marcus explained they also found coffee could affect the heart as well. On days where participants consumed more than one cup of coffee per day, they were 50% more likely to have an incidence of premature ventricular contractions (PVCs), which are extra heartbeats that start in one of the heart’s two lower pumping chambers, also known as the ventricles.
“Both randomized assignments to consume coffee and the amount of coffee consumed were associated with more premature ventricular contractions,” Dr. Marcus noted. The reason for this is possibly related to the participant’s “genetic propensities” and how quickly they were able to metabolize or absorb the caffeine.
Other experts note that too much caffeine can be concerning for those who have an existing heart condition or problem because the stimulant effects of high caffeine consumption can make your heart beat even faster.3
“They looked at people with normal hearts without evidence of disease and found no increased risk,” Hal Skopicki, MD, PhD, Chief of Cardiology and Co-Director of the Stony Brook Heart Institute, told Health in an email.
“That doesn’t mean that caffeine wouldn’t exacerbate events in someone who already has it or has a heart muscle that is predisposed to these types of arrhythmias.”
The Link Between Coffee, Exercise, and Sleep
One potential reason why coffee may impact someone’s ability to sleep is that caffeine gets quickly absorbed throughout the body, including the brain. This allows people to feel more alert and awake, Wahaj Aman, MD, an interventional cardiologist with UTHealth Houston and Memorial Hermann in Texas, told Health.
Dr. Aman explained that once caffeine is absorbed by the body, it can block adenosine receptors, which are sleep-promoting chemicals that are produced in the brain when we are awake. The longer we are awake, the more adenosine builds up and the sleepier we can become, however, when caffeine is consumed, it can block this process and disrupt overall sleep.
One 2013 study found that 400 mg of caffeine taken 0, 3, or 6 hours before bed significantly disrupts sleep. In addition, consuming coffee 6 hours before bed also reduced sleep by more than 1 hour.4
Dr. Skopicki noted that caffeine can boost energy, as well as endurance and muscle contraction, which is a potential explanation for why the participants in the study who consumed coffee had more steps in a day compared to those who did not consume any at all. He adds coffee can also reduce a person’s perception of how much effort they are truly exerting when they are exercising.
“Although I am not advocating it, many athletes consume caffeine to improve their exercise tolerance,” he said. “Caffeine also enhances the use of fat as fuel during exercise, which may be beneficial for endurance athletes. By sparing the body using its storage sugar, glycogen, athletes may maintain their energy level for longer periods of time and delay the onset of fatigue.”
Dr. Marcus explained that while they do not know the exact reasons why people took more steps when exposed to coffee, previous research suggests caffeine may boost physical performance making exercise easier after coffee consumption.5
“There is also an activating effect of caffeine on the central nervous system, which may have contributed to greater motivation to engage in physical activity,” he added.
However, Dr. Skopicki and Dr. Marcus agreed that more research is needed to determine the effects of coffee on sleep and exercise and when coffee-related physical activity might result in better health.
Cutting Back on Caffeine
Despite the study’s findings, Dr. Aman clarified that there’s no definitive or clear answer on whether or not people should drink more coffee or cut back. Deciding to do one or the other will depend on your lifestyle, health conditions, and experiences or tolerances with coffee.
For example, people who struggle with insomnia or have other sleep disorders may benefit from cutting back on coffee consumption or cutting coffee out altogether. On the flip side, if you don’t normally have any sleep issues but tend to be more sedentary, consuming coffee may give you more energy and potentially boost physical activity.
“Given the complex nature of our findings, I would not propose a universal or one-size-fits-all response to these findings,” Dr. Marcus concluded. “Instead, I hope this information can be digested and utilized to fit with each individual’s health goals.”