RELATED: This Popular Diet Is a “Disease-Promoting Disaster” New Study Says. Many athletes seeking to enhance their performance rely on caffeine for a pre- or mid-workout boost. Yet experts have found that there may be a potentially serious side effect to your preferred pick-me-up. In a recent study published in the journal Medicine & Science in Sports & Exercise, researchers learned that drinking caffeine increases coagulation during acute sessions of strenuous exercise, putting you at higher risk for blood clots.ae0fcc31ae342fd3a1346ebb1f342fcb The research team orchestrated two workout sessions for 48 young men with an average age of 23 and normal body mass index. Study participants were given a beverage—first a placebo and later a caffeine-laden drink—before completing a challenging workout on an exercise bike. They then had their blood drawn. The researchers observed that after consuming caffeine, coagulation levels were significantly higher, putting the study subjects at elevated risk of conditions such as heart attack, stroke, deep vein thrombosis, or pulmonary embolism. RELATED: The Major Negative Effect of Drinking Ice Water You Didn’t Know, Study Says. However, some experts say that while caffeine may indeed elevate coagulation levels, this doesn’t mean everyone is at serious risk of clotting. “For most people, caffeine is safe, and so is exercise,” Paul Nagelkirk, PhD, the director of the Integrative Exercise Physiology Laboratory at Ball State University, told Runner’s World in 2019. “Healthy adults who currently enjoy the benefits of caffeine as a pre-workout or pre-competition routine have little reason to worry about blood-clotting potential,” he added. However, those with high blood pressure, high cholesterol, or a history of smoking—all blood clotting risk factors—may wish to avoid caffeine surrounding their workout. So, just how much caffeine is too much? According to the Mayo Clinic, “Up to 400 milligrams (mg) of caffeine a day appears to be safe for most healthy adults.” Their experts note that 400 milligrams is equivalent to roughly “four cups of brewed coffee, 10 cans of cola or two ’energy shot’ drinks.” Some people, including those who are pregnant, wishing to become pregnant, or are currently breastfeeding, may benefit from limiting their caffeine intake to under 200 milligrams daily. Even among healthy adults with no notable health considerations, “caffeine may not be a good choice for people who are highly sensitive to its effects,” adds the Mayo Clinic. For more health news sent directly to your inbox, sign up for our daily newsletter. If you wish to limit your intake, the Mayo Clinic says it’s best to cut out caffeine powders and pills, which can have staggeringly high amounts of caffeine in them—more than consumers often realize. “Just one teaspoon of powdered caffeine is equivalent to about 28 cups of coffee. Such high levels of caffeine can cause serious health problems and possibly death,” the clinic warns. The further note that energy drinks—for some considered a workout staple—differ widely in the caffeine content depending on brand. “Keep in mind that the actual caffeine content in beverages varies widely, especially among energy drinks,” the Mayo Clinic says. Given the elevated risk of clotting associated with exercise, this is especially important advice for those who rely on the beverage as part of their gym routine. RELATED: Drinking a Cup of This a Day Can Slash Your Stroke Risk, New Study Says.