People who exercise the same amount have different levels of cardiorespiratory fitness, and scientists aren’t sure why. They may be closer to an answer, however. A study led by researchers from Beth Israel Deaconess Medical Center in Boston and Boston University found that substances produced during digestion and released into the body during exercise, known as metabolites, play a role in determining the kind of cardiorespiratory fitness a person is likely to develop from exercising.
Michael Mi, lead author of the study, told TheDoctor that if the body is metabolically healthy, it may respond better to exercise. Metabolic health also probably does a better job of protecting the health of the circulatory system and muscles, and improves the muscles’ ability to use nutrients; and this could boost the fitness dividends a person gains from exercise. “I think the underlying status of the health of the body and how that promotes better fitness should not be underestimated,” added Mi, an instructor of medicine at Beth Israel Deaconess Medical Center in Boston.
People should not change their diet just because they think it will make them fitter, Mi advised. “People who eat a healthy diet are more likely to have a healthier lifestyle in general. We are just adding to the literature that eating better has many benefits for your health.”
The metabolites associated with a high-quality diet and higher fitness levels have been shown in other studies to lower the risk of diabetes, cardiovascular disease, heart attacks and early mortality.
The average scores on the Alternative Healthy Eating Index and the Mediterranean-style Diet Score were 66.7 and 12.4, respectively. An increase of 13 points from the average score on the Alternative Healthy Eating Index was associated with a 5.2 percent greater peak oxygen uptake. An increase of 4.7 points on the Mediterranean-style Diet Score was associated with a 4.5 percent greater peak oxygen uptake.
Blood samples were collected from a subgroup of more than 1,100 participants to measure the amounts present of about 200 metabolites, such as amino acids and ceramides. Twenty-four metabolites were associated with poor quality diet and lower fitness levels or high-quality diet and higher fitness levels. The beneficial metabolites have been shown in other studies to lower the risk of diabetes, cardiovascular disease, heart attacks and early mortality, Mi explained.
Mi and his team are doing more work to understand more specifically how metabolites affect the body: “We are always probing how metabolites may relate to health outcomes, which can give us a better sense of what these metabolites mean.” Their next step is to look at how proteins measured in the blood reflect the relationship between diet and the overall health of the body.