Can you be fit yet inflamed?
June 12, 2025
I spoke with The Times and the Telegraph recently about inflammation, diet and disease, and one of the recurring themes was physical fitness and inflammation:
This statement is overwhelmingly true. Physical, visible “fitness” seems to be a proxy for optimal health and wellness. But even if an individual appears ultra-fit and devoid of excess body fat, inflammation may nonetheless simmer underneath the surface. While exercise generally dampens inflammation, it can actually trigger excessive inflammation if not performed properly, including from issues like overtraining, exercising in the wrong way, or failing to schedule adequate recovery periods.
A fit, frequent gym-goer can also suffer with hidden inflammation due to an unhealthy diet, or even an ostensibly healthy diet that includes ultra-processed “health” foods that are not truly nutritious. Or perhaps the individual has optimized diet and exercise but faces other inflammatory exposures, like a high-stress lifestyle, inadequate sleep, poor air quality, chemical exposures, or undiagnosed infections. The inflammatory exposome—the external and internal factors a person is exposed to from birth to death that can lead to chronic inflammation–is vast.
Conversely, the following holds true as well:
Exercise, even in the absence of weight loss, can melt inflammatory visceral fat deep within the body and lower the numbers of immune cells infiltrating fat tissue. This is a remarkable notion, and one that reminds us that the most valuable gains from lifestyle habits like diet and exercise are not necessarily about the image in the mirror or the number on the scale. The bodily benefits, the imperceptible biological changes accruing from humble, daily habits, are hidden—as is the inflammation they are fighting—but they cannot be discounted.
Inflammation may be the culprit behind our deadliest diseases | TIME
April 11, 2023
By. Shilpa Ravella
That inflammation is a common element in humankind’s top killers—heart disease and cancer—is unlikely to be serendipitous. The intricate link between inflammation and modern chronic diseases is rooted in our evolutionary history. In order to survive infections, famine, and other dangers in brutish ancestral times, we developed hyperactive immune systems and insulin-resistant bodies adept at storing fat. But our modern environment has been markedly transformed, from the food we eat to the air we breathe, how we move and more. Our immune system is exceptionally sensitive to the triggers of this new world, portending a higher risk of chronic, hidden inflammation.
In the 21st century, as hidden inflammation weaves through our deadliest diseases, unveiling this force—seeing what has long been unseen—is poised to make its mark on medicine.
Gut microbiome: another reason to exercise
April 30, 2017
In 2014, researchers comparing the National rugby team of Ireland and sedentary men reported in the journal Gut that being physically fit was associated with a greater diversity of gut bugs. But correlation vs causation was debated, as with many microbiome studies.
Newer research conducted in rodents has found that exercise, regardless of diet type, improved the makeup of the gut microbiome and raised the levels of butyrate, a short-chain fatty acid that nourishes the intestinal barrier and helps protect against colon cancer. Rob Knight, director of the Center for Microbiome Innovation at U.C. San Diego, told Vogue, “That people who move more have a more diverse microbiome is something that we noticed at my lab several years ago, but we couldn’t prove causality…these studies are incredibly exciting”
The newest research conducted by the same authors of the 2014 study showed that athletes had increases in beneficial fecal metabolites like short-chain fatty acids. “Our earlier work, also published in ‘Gut’, had shown that the microbiome of the athletes differed in composition from that of non-athletes, but now we have found that functional behaviour of the microbiome separates the athletes and controls to an even greater degree,” said Professor Fergus Shanahan, one of the study’s lead authors.