Advertisement
Advertisement
Advertisement
Bicycling

Can Taking Caffeine During Your Workout Actually Be Dangerous?

Elizabeth Millard
Photo credit: skynesher - Getty Images
Photo credit: skynesher - Getty Images

From Bicycling

  • Taking caffeine during a high-intensity workout can increase the coagulation factor in your blood, making it more likely to form clots, according to a new study in the journal Medicine & Science in Sports & Exercise.

  • Increasing this coagulation factor can be dangerous in people with other risk factors for heart disease, like high blood pressure, high cholesterol, or obesity. But healthy people are not at the same risk.

  • Limiting your caffeine to no more than 400 milligrams per day is still recommended.


Using caffeine as a preworkout prep and during-exercise booster is quite common, and can offer some real performance benefits, as we’ve reported before. But, a new study throws a wrench its way, finding that the habit may be linked to higher chances of forming blood clots-which can lead to life-threatening effects in some people.

In the study, which was published in Medicine & Science in Sports & Exercise, researchers looked at 48 men, with an average age of 23, and a normal body mass index. The participants completed two sessions, a week apart, on exercise cycles that were gradually increased in speed until participant exhaustion-making it a high-intensity workout. They were given either a non-caffeinated placebo or a caffeinated drink beforehand, and their blood was drawn before and after, along with vital signs reporting.

Advertisement
Advertisement

They found that caffeine significantly increased the coagulation factor during exercise, meaning that the participants who had the caffeine drinks had a higher risk factor when it comes to what causes blood clots. That’s important, since blood clots can cause things like stroke, deep vein thrombosis, heart attack, and pulmonary embolism.

But does this mean everyone should consider ditching their caffeinated energy gels or chews? Not at all, said lead researcher Paul Nagelkirk, Ph.D., the director of the Integrative Exercise Physiology Laboratory at Ball State University.

That’s because the increase in the coagulation factor affects those with other cardiovascular risk factors-think obesity, smoking, high blood pressure, or high cholesterol. People with these risk factors are more likely to experience a cardiovascular event as a result of the increased clotting potential.

“For most people, caffeine is safe, and so is exercise,” he told Runner’s World. “Healthy adults who currently enjoy the benefits of caffeine as a preworkout or precompetition routine have little reason to worry about blood-clotting potential.”

Advertisement
Advertisement

One potential issue, though, may be lots of people don’t really know where they fall on the “healthy” scale. Although you know whether you smoke or not, or fall into the obese category, it’s the other factors that can get tricky.

“There are people who are apparently healthy, but who have an underlying pathological condition that puts them at risk,” Nagelkirk said.

That means even if you think your blood pressure and cholesterol are fine because you’re fit, it’s possible that they could high due to an inherited condition, for example. Knowing your numbers, and checking them on a regular basis, is crucial for knowing how healthy you really are.

If you’ve checked your numbers and do fall into the healthy zone for blood pressure and cholesterol, there’s still a limit when it comes to safe caffeine consumption, Nagelkirk said. The general recommendation is to get under 400 milligrams (mg) of caffeine per day.

Advertisement
Advertisement

“The amount of caffeine in most commercial products is well within these limits, and is considered safe for most people,” he said. “Dangerous levels are most likely consumed by people who use caffeine in powdered or pill form, and who ignore the dosage precautions.”

But that 400-mg max includes all your caffeine for the day, so make sure you’re including your morning cup (or cups) of coffee in your tally, as well as what you are taking in during your workout.

Plus, it’s not like taking in more caffeine will make your workout any better: Past research doesn’t show any positive performance benefits to going past recommended limits, he said.

[Find 52 weeks of tips and motivation, with space to fill in your mileage and favorite routes, with the Bicycling Training Journal.]

Advertisement
Advertisement

If you do have cardiovascular risk factors? It doesn’t necessarily mean you have to shelve caffeine during your workouts entirely-you just many need to lower the intensity of your exercise when you use it.

“Lower-intensity exercise does not increase blood-clotting potential the same way vigorous-intensity exertion does,” said Nagelkirk. “Still, people who have a number of cardiovascular risk factors might want to weight the benefits of caffeine use in light of the potential increased risk.”

('You Might Also Like',)

Advertisement
Advertisement