Two new studies provide more evidence that exercise is critically important for both the prevention and management of type 2 diabetes.
In the first, researchers conclude that telling patients with type 2 diabetes to "Take a short walk right after meals" may be one of the best exercise prescriptions a clinician can give.
Results from the randomized crossover study show that postmeal blood glucose levels dropped 12%, on average, when patients with type 2 diabetes walked for 10 minutes after three daily meals compared with walking for 30 minutes at any time of day (P = .034).
Most of this effect came from a 22% glycemic drop in the 3-hour period following the after-dinner walk, particularly when the meal was carbohydrate-heavy, say Andrew N Reynolds, MD, from the University of Otago in Dunedin, New Zealand, and colleagues.
"The improvement was particularly striking after the evening meal when the most carbohydrate was consumed and sedentary behaviors were highest," they say in their paper published October 17 in Diabetologia.
Since postprandial glycemia is an independent determinant of glycemic control as well as cardiovascular risk, the timing of physical activity may provide significant additional health benefits to patients with type 2 diabetes, Dr Reynolds and colleagues point out.
Guidelines Should Be Updated With This Easy Advice
The findings also make a strong case for updating current guidelines, the researchers assert.
"The benefits relating to physical activity following meals suggest that current guidelines should be amended to specify postmeal activity, particularly when meals contain a substantial amount of carbohydrate."
Current activity guidelines recommend that patients with type 2 diabetes get a minimum of 150 minutes of moderate physical activity each week, or about 30 minutes a day over 5 days. Daily exercise can be completed at one time or at different times throughout the day.
Postprandial physical activity may make it possible for patients to avoid an increased total insulin dose or additional mealtime insulin injections to lower glucose levels after eating, Dr Reynolds said in an interview.
Higher insulin doses might, in turn, be associated with weight gain in patients with type 2 diabetes, many of whom are already overweight or obese.
"What is surprising is how easily this advice can be communicated to patients with type 2 diabetes," he told Medscape Medical News. " 'Go for a walk after your meals' " is a very clear message to deliver to your patients and then to follow up at each subsequent clinical visit."
Since the prescribed level of activity was so modest (30 minutes total each day), the results may be applicable to a wide group of patients with type 2 diabetes mellitus, Dr Reynolds added.
Study Details
The postmeal walking study, conducted at the University of Otago between September 2013 and February 2015, enrolled 41 patients with a mean age of 60 years. Mean duration of diabetes was 10 years.
Patients were randomized to an exercise prescription of 2 weeks of walking 30 minutes each day or to walking for 10 minutes right after three daily meals. After the 30-day washout period, participants switched to the other exercise prescription. No changes were made to diet or to other lifestyle factors.
Patients wore accelerometers to measure physical activity as well as continuous glucose-monitoring systems.
Interestingly, patients walked longer when they walked after meals, although the researchers aren't sure why.
"Prescriptions were matched in activity and duration and differed only with regard to the specified time of walking," Dr Reynolds explained to Medscape. "While we do not have the evidence to comment on why this is so, there are important clinical repercussions to this finding."
Future studies that include biochemical or cell-based measurements may reveal how increased walking after meals reduces blood glucose levels.
In the meantime, the researchers are conducting follow-up research to identify factors that motivate or prevent people with type 2 diabetes from following a regular walking prescription, which they hope will be of use to physicians to help promote adherence to regular walking routines; they expect to publish this work soon, Dr Reynolds said.
More Exercise Always Better When It Comes to Preventing Diabetes
Results from the second study further inform when it comes to the dose-response relationship between exercise and the development of type 2 diabetes.
This was a meta-analysis of 23 cohort studies in 1.2 million nondiabetic individuals from the United States, Asia, Australia, and Europe, showing that those who achieved a 11.25 metabolic equivalent of task (MET) hours/week of moderate activity (the 150 minutes/week currently recommended) had a 26% reduction in the risk of developing type 2 diabetes.
Those whose physical activity reached 60 MET hours/week, however, reduced their risk of developing diabetes by an even greater amount, more than 50%, said lead author Andrea Smith, a PhD candidate in public health at the Health Behaviour Research Centre at University College London, United Kingdom, and colleagues.
The work is also published on October 17 in Diabetologia,
"Our study favors a 'some is good but more is better' guideline, in which specific targets are mainly used for a psychological effect," say the researchers.
"There is no clear cutoff at which benefits are not achieved, and health benefits increase at activity levels well beyond current recommendations."
Funding for the New Zealand study was provided by the University of Otago and the New Zealand Artificial Limb Service. Funding for the UK study was provided by the Centre for Diet and Activity Research (CEDAR). The authors from both studies disclosed no relevant financial relationships.
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Diabetologia. Published online October 17, 2016. Reynolds abstract, Smith abstract
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Cite this: A Stroll After Supper Is Good Advice for Type 2 Diabetes Patients - Medscape - Oct 19, 2016.
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