NEW STUDY SAYS HIGH-INTENSITY INTERVAL TRAINING (HIIT) CAN CAUSE MITOCHONDRIAL DYSFUNCTION
By Steve Blechman
The mitochondria are the engine powerhouses of the cell, generating energy by burning fat, sugar and certain amino acids from the foods we eat into ATP for proper cellular energy and function. Mitochondrial dysfunction could be caused by aging, oxidative stress, and energy metabolism. Mitochondria damage can cause insulin resistance and diabetes; increased body fat and obesity, lower exercise capacity, muscle strength and cognitive function. In a new study published in the March 18th, 2021 issue of the journal Cell Metabolism, a team of Swedish researchers reported that excessive high-intensity-interval training (HIIT) can cause mitochondrial dysfunction and insulin resistance. The researchers found that “excessive exercise training induces substantial respiratory impairment” and that “mitochondrial impairment is associated with impaired glucose tolerance.” HIIT training involves short burst of high-intensity exercise interspersed with a few minutes of rest or lower intensity exercise to enhance recovery. Research has shown that the benefits and advantages of HIIT training is that you can get maximum health effects in the least amount of time. Studies have shown that high-intensity interval training can increase muscle mitochondrial biogenesis, protein synthesis and enhance mitochondrial function and cardiorespiratory fitness. But is more HIIT training better? Not necessarily, according to this new study. With test subjects performing HIIT training on a stationary bike, the researchers “used a training model with a progressively increasing exercise load during an intervention of four weeks.” The researchers said, “we closely follow changes in glucose tolerance, mitochondrial function and dynamics, physical exercise capacity and whole-body metabolism. Following the week with the highest exercise load, we found a striking reduction in intrinsic mitochondrial function that coincided with the disturbance in glucose tolerance and insulin secretion. We also assessed continuous blood glucose profiles in world class endurance athletes and found that they had impaired glucose control compared with the match control group.” During the study, the researchers performed muscle biopsies of the exercise subjects to measure mitochondrial function as well as glucose measurements to monitor insulin levels. The insulin resistance was similar to someone with diabetes. Also, mitochondrial respiration fell by an average of 40%. But oxygen consumption and power output levels improved. The shortcoming of this study is that it was small and only involved 11 adults that exercised regularly, but not competitive athletes. A larger study is needed over a longer period of time to see if the same results occur. The bottom line is the health benefits of exercise are clear. High-Intensity interval training (HIIT) is safe and very effective workout for improving health and performance. It is not necessary to do HIIT training every day. Do HIIT training two to three times weekly, and on other days of the week do moderate-intensity exercise of longer duration to achieve optimum metabolic health, fat loss and aerobic fitness. To enhance muscle performance and recovery after high-intensity exercise, take mitochondrial regulator and protector nutrients such as leucine (5 grams), creatine monohydrate (5 grams) and betaine (2.5 grams) as present in Advanced Molecular Labs (AML) Post Workout. Research has shown that these mitochondrial activators can help enhance and preserve skeletal muscle mitochondrial biogenesis and function.
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