Tuesday October 18 2016
Walking after meals helped lower blood sugar
"Short stroll after meals better for blood sugar than walks at other times," says The Daily Telegraph.
The story is based on a study which aimed to see whether taking a 10-minute walk after a main meal resulted in lower blood glucose levels than a single 30-minute walk each day for people with type 2 diabetes.
The study, which involved 41 adults, found that taking shorter, more frequent walks immediately after meals reduced blood glucose by around 12% compared with a single 30-minute walk.
The greatest benefit was seen after the evening meal when carbohydrate consumption was high and participants tended to be less active.
The researchers did not explain why a post-meal walk was more effective at lowering glucose in the blood. However, they believe a short stroll after every meal could reduce the need for insulin injections which can help people better manage their weight.
Researchers say current physical activity guidelines should be changed to specifically include post-meal activity, especially after meals with lots of carbohydrate, such as bread, rice, potatoes and pasta.
There are 4 million people living with diabetes in the UK and 90% of those have type 2 diabetes, according to Diabetes UK. Type 2 diabetes occurs when the body doesn't produce enough insulin to function properly, or the body's cells don't react to insulin.
Due to the short duration of this study we can't be sure that the effect seen in this research would last and lead to an overall improvement in blood glucose levels and diabetes control.
However, the findings are interesting and if confirmed by further research, could mean this simple lifestyle change would benefit people with diabetes.
Where did the story come from?
The study was carried out by researchers from the University of Otago in New Zealand. It was supported by grants from the University of Otago and the New Zealand Artificial Limb Service. Glycated albumin reagents were provided by Asahi Kasei.
The study was published in the peer-reviewed medical journal Diabetologia.
Reporting of the study by the media was broadly accurate. But, as the study was carried out in people with diabetes it is perhaps misleading to say that it "cuts risk" as suggested in the Daily Express.
What kind of research was this?
This was a randomised crossover study which aimed to assess whether the timing of walking in relation to meals could benefit people with diabetes by reducing their blood sugar levels.
This study design is a good way of testing for such benefits as participants act as their own controls and are randomly assigned to the intervention groups. In theory, this should balance out any differences in characteristics and potential confounders between participants, meaning the effect seen is due to the intervention rather than the influence of other factors.
As physical activity lowers blood glucose levels, it's important for people with diabetes to exercise regularly. Current advice is to do 150 minutes of moderate aerobic activity a week, such as cycling or fast walking.
This study attempted to examine whether taking 10 minute bursts of exercise after each main meal proved to be of greater benefit than a single 30 minute stretch.
What did the research involve?
Adults aged 18 to 75 years with type 2 diabetes were included in the study. Recruitment was from general practices, hospital outpatient clinics, a local diabetes society and services for people with chronic diseases. Those who were pregnant, breastfeeding, and unable or unwilling to comply with the required physical activity were not included.
The participants were randomly assigned to one of the two intervention groups, each intervention lasted 14 days followed by a 30 day break. The participants then crossed over to the intervention they had not yet received. The two interventions were:
- a 30 minute walk each day
- a 10-minute walk following each main meal
Activity information, including walking and sitting time and other sedentary behaviours, was collected using an exercise monitor device worn during waking hours for the 14 days of the study.
The main outcome was the level of glucose in the blood after a meal (postprandial glycaemia), which was assessed during the three hours after a meal.
Dietary data was analysed using food composition tables.
On days 1, 7 and 14 of each intervention participants visited the clinic for the following assessments:
- Day 1 – fasting blood sample was drawn, body measurements were taken, the physical activity regimen was prescribed and exercise monitors were fitted.
- Day 7 – participants were fitted with a continuous glucose monitoring system and given a portable glucometer. A seven day food diary was started.
- Day 14 – fasting blood sample was drawn, body measurements were taken, the glucose and exercise monitors were removed and food diary was returned.
The same set of procedures was followed with both interventions.
What were the basic results?
The researchers included 41 adults with an average age of 60 years who had diabetes for an average of 10 years.
The study found that when participants walked after meals the level of blood glucose was 12% lower than in those who went for a single walk each day.
The improvement was greatest after the evening meal, 22%, when carbohydrate consumption was generally highest. This is also the time of day when people were most likely to be active.
There were no side effects related to the two different approaches. One person died during the 30-day break, but this was not related to the trial.
How did the researchers interpret the results?
The researchers concluded that post-meal "physical activity may avoid the need for an increased total insulin dose or additional mealtime insulin injections that might otherwise have been prescribed to lower glucose levels after eating.
"The benefits relating to physical activity following meals suggest that current guidelines should be amended to specify post-meal activity, particularly when meals contain a substantial amount of carbohydrate."
This randomised controlled crossover trial aimed to assess whether taking a 10 minute walk after each main meal provides additional benefit in lowering blood glucose in people with type 2 diabetes compared with a single 30 minute daily walk.
The study found that taking shorter, more frequent walks after meals produced lower blood sugar estimates than a single walk. The researchers believe that, based on these findings, current guidelines should be changed and specify post-meal activity especially if the meal is high in carbohydrate.
This study was well designed and made efforts to reduce the risk of chance findings.
A limitation of this study is the short duration. We can't be sure if the benefits of a post-meal walk are long term and we don't know if the differences in blood glucose seen (about 0.5mmol/l lower) would make a meaningful difference in terms of these people's diabetes control.
Participants were not monitored during the trial break, so we do not know what their diet and exercise habits were during this time, and this may have had an impact on the overall findings.
We also do not know if this exercise routine would reduce the risk of diabetes in people who don't have diabetes or those with pre-diabetes.
The researchers did not explain why a post-meal walk was more effective at lowering glucose in the blood.
However, they believe a short stroll after every meal could reduce the need for insulin injections which can help people with diabetes to better manage their weight.
The findings of this research are certainly interesting and if they are confirmed to be accurate by further research, it would mean this simple lifestyle change would benefit people with diabetes.