Exercise does a body good—until it doesn't. Case in point, you may have seen the research back in September that discovered Cross-Fit-style workouts done two days in a row can beat up your immune system. Grueling routines are said to lower white blood cells—your first line of defense against infection—thereby leaving you susceptible to colds and the flu. (Regular moderate exercise does the opposite; it protects your body from upper respiratory sickness.)

But new American Physiological Society research is offering up a simple solution: Consume carbs in the midst of exhausting workouts to safeguard your immune system.

Sound too goo to be true? First, a quick exercise science primer. Workouts put your body under stress. And, stress hormones that modulate your immune system respond to how hard and how long you exercise, study co-author Jonathan Peake explained to The New York Times. For the most part, the more strenuous your WOD, cycling class, or sprint workout is, the longer it takes for your immune system to normalize (white blood cells to return to normal levels).

In the past, experts believed exercise destroyed white blood cells; but Peake notes in the NYT, it’s more likely they move out of the bloodstream and to other areas of your body in need, like your screaming lungs and overheating skin (because the tissues are undergoing a change due to stress and/or you're inhaling or come into contact with something that requires an immune response, he explains.  

Where carbs come into play: Carbs, as you may know, help maintain blood sugar levels. And having stable blood sugar levels dampens your body's stress response, which then prevents your immune cells from scrambling around your body, study co-author Oliver Neubauer told the NYT. For high-intensity bouts or long workouts that last 90 minutes or more, you'll need about 30-60 grams of carbs per hour of exercise, Neubauer suggests. He adds: Eating or drinking carbs in the first few hours after strenuous exercise will also help restore proper immune function, too. Read the full Q&A at The New York Times

7 ways to boost your endurance and stamina

Fending off colds isn't the only benefit of consuming carbs mid-workout. Find out how else the macro can enhance your health and fitness on the following slides.