Crunched for time? Intensive exercise = same cellular benefit in less than minutes

According to new research, a few minutes of high intensity interval or sprint exercise can be as effective as much longer exercise sessions to stimulate beneficial improvements in mitochondrial function . The small study is published before printing in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology.

Mitochondria, the energy centers of cells, are essential for good health. Previous research has shown that exercise creates new mitochondria and improves the function of existing mitochondria. Alteration of mitochondrial function in response to a single exercise session generates signals that can lead to beneficial changes in the cells, thereby reducing the risk of chronic disease. High intensity interval training consists of short periods of high intensity aerobic exercise – physical activity that increases the heart rate – alternating with brief periods of recovery. It is not known if the intensity of a workout affects the mitochondrial response.

A team of researchers studied eight young adult volunteers while participating in variable intensity cycling training.

• Moderate intensity consisted of 30 minutes of continuous exercise at a maximum effort of 50%.
• The high-intensity interval exercise consisted of five four-minute cycling sessions with a maximum effort of 75%, each separated by a minute of rest.
• Sprint cycling consisted of four 30-second sessions with maximum effort, each separated by 4.5 minutes of recovery time.

The research team measured the amount of energy that volunteers spent at each training session and compared mitochondrial changes in the thigh muscles of participants before and after each session of the team. 39; exercises. The researchers found that levels of hydrogen peroxide – a type of molecule involved in cell signaling called "reactive oxygen species" that contains oxygen and hydrogen – in different parts of the mitochondria change after exercise. Although too much reactive oxygen could be harmful to the cells, the researchers noted that volunteer levels constituted an appropriate amount to potentially promote beneficial cellular responses for metabolic function rather than causing damage.

In addition, the research team found that fewer minutes of higher intensity exercise produced mitochondrial responses similar to longer moderate intensity activity. "A total of just two minutes of exercise at sprint intervals was enough to cause similar responses to 30 minutes of continuous moderate intensity aerobic exercise," the researchers wrote. "This suggests that exercise can be prescribed according to individual preferences while generating similar signals known to confer beneficial metabolic adaptations.These findings have important implications for improving our understanding of how exercise improves." metabolic health in the general population. "

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More information:
Adam James Trewin et al., Acute HIIE causes similar changes in the release of mitochondrial H2O2 in human skeletal muscle, respiration and cellular signaling as endurance exercise, even with less work, American Journal of Physiology Regulatory, Integrative and Comparative Physiology (2018). DOI: 10.1152 / ajpregu.00096.2018