Why Dr. Sasse recommends it for all his patients, and why it might be good for you, too.
Zone II (out of 5 zones) exercise is most commonly defined as the kind of exercise that is not the easiest level (Zone I) of a slow walk, but it is a level at which one can still carry on a conversation. Think of moderate bicycling, a brisk walk or a jog.
What seems to be so special about this form of exercise is its effect in increasing the density and performance of mitochondria in skeletal muscle, and perhaps elsewhere in the body. Dr. San Millan in Denver and researchers in other centers have examined the importance of mitochondrial function in metabolic syndrome and obesity. And what they have found is both quite striking and somewhat encouraging: the mitochondria can demonstrate an important lack of flexibility in utilizing different forms of fuel, from lipids to carbs, and this may be the key to what causes obesity and diabetes. But the mitochondrial performance can improve with even moderate Zone II exercise.
The mitochondrial finding is important for several reasons: First, when these energy factories increase in number and work harder, the body is more likely to maintain a healthy body weight. Second, the mitochondria play a key role in insulin sensitivity, maintaining normal blood sugar, and avoiding the metabolic syndrome.
Interestingly, exercise is increasingly being found to play an important role in a number of processes that affect people battling excess weight and obesity. Among them is the new finding exercise inhibits the progression of non-alcoholic fatty liver disease (NAFLD). The most encouraging piece of this research is that everyone can do some Zone II exercise, and in fact, most people can do a lot of it. With health benefits ranging from cardiovascular health, liver stability, diabetes prevention, and anti-aging, it may be time for all of us to find more minutes in the day for a brisk walk.
References:
1. Prasun, P., 2020. Mitochondrial dysfunction in metabolic syndrome. Biochimica et Biophysica Acta (BBA)-Molecular Basis of Disease, p.165838.
3. DiMenna, F.J., Arad, A.D. Exercise as ‘precision medicine’ for insulin resistance and its progression to type 2 diabetes: a research review. BMC Sports Sci Med Rehabil 10, 21 (2018). https://doi.org/10.1186/s13102-018-0110-8
4. Guarino, M., Kumar, P., Felser, A., Terracciano, L.M., Guixé-Muntet, S., Humar, B., Foti, M., Nuoffer, J.M., St-Pierre, M.V. and Dufour, J.F., 2020. Exercise Attenuates the Transition from Fatty Liver to Steatohepatitis and Reduces Tumor Formation in Mice. Cancers, 12(6), p.1407.
