Interval exercise ideal to thwart diabetes development

Researchers at the University of Virginia have found that 30 minutes per day for five days a week of high-intensity interval exercise can help head off the development of diabetes mellitus in pre-diabetes patients.

Steven K. Malin, PhD, director of the Applied Metabolism & Physiology Laboratory and the University of Virginia’s Curry School of Education, says he and his team sought to answer what factors-aside from genetics-are contributing to the increasing number of diabetes mellitus diagnoses and what interventions could be employed in at-risk patients. The team is also investigating whether high blood glucose levels can be mitigated through increased blood flow and resulting pancreatic function, which can enhance the effects of insulin on skeletal muscle, the liver, or adipose tissue metabolism.

Overall, high-intensity interval exercise on a bicycle was found to be beneficial for patients with pre-diabetes, not considering weight loss as a factor. However, not all patients responded the same.

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Recruitment has focused on patients with pre-diabetes, and Malin found that patients with high blood glucose levels in the fasted state plus high glucose after meals have poorer responses to exercise that those with high fasting or high meal glucose levels.

“This suggests to us that not all people with pre-diabetes are the same,” Malin told Medical Economics. “As a result, we are interested in knowing if interval exercise can improve blood glucose levels in people with high fasting and high meal glucose to exercise to similar levels as those with high meal glucose levels only.”

Malin adds that he has found that characterizing blood glucose levels based on fasting and two-hour glucose levels may be helpful in identifying the type of pre-diabetes a person has.

“Often times only fasting blood glucose or HbA1c levels are measured. Rarely are blood glucose levels recorded two-hours following an oral glucose tolerance test in the primary care office,” Malin says. “This is important because some people may have normal fasting glucose levels yet impaired meal glucose levels only. This is clinically important for the primary care physician since patients with impaired meal sugar levels have higher risk for future diabetes and cardiovascular disease than high fasting glucose levels only.”

Patients generally responded better overall to just two weeks of higher intensity exercise than continuous exercise at the same intensity.

NEXT: Skeletal muscle may also be to blame for higher glucose levels

Malin’s research has determined that 150 minutes of exercise each week can delay the onset of diabetes mellitus by about 58% when compared to those who live unhealthy lifestyles.

“Research has shown too over the last five to 10 years that performing this type of exercise presents little risk for heart problems assuming the person has no underlying issue and it is safe for them to exercise,” Malin says. “As a result, promoting higher intensity exercise for a few minutes spaced out with very light exercise for 30 to 60 minutes a day can have more profound effects on blood sugar control when compared with traditional exercise.”

While genetics and lifestyle choice certainly play a role in the development of diabetes, Malin and his team estimate that problems with skeletal muscle may also be to blame for higher glucose levels.

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“It is thought that skeletal muscle does not respond properly to [insulin]. While this is likely a key issue in the development of diabetes, we are studying if blood flow to the muscle is actually impaired. That is, we are determining whether blood sugar can even get to the muscle in the blood,” Malin says. “This has not been tested before and if blood flow is limited in people with different types of pre-diabetes, it would suggest a new and personal target for treating patients with pre-diabetes, and determine how exercise might be improving blood glucose levels.”

Malin stresses that in his studies, patients did not necessarily have to lose weight to experience metabolic health benefits from this type of exercise.

“This is important because sometimes people struggle to lose weight and become frustrated. Our results, and those reported by others, show that increasing fitness can protect many of the obesity associated health risks,” Malin says. “As a result, the primary care physicians should consider informing patients that exercise will promote health benefits before any significant weight loss. This effect alone will reduce risk of diabetes disease progression and, importantly, begin promoting the normalization of high blood glucose levels.”