Seniors are more prone to developing diabetes, but a little exercise could make a big difference. A study published today in Diabetes Care found that three short walks each day after meals were as effective at reducing blood sugar over 24 hours as a single 45-minute walk at the same moderate pace.
Even better, taking an evening constitutional was found to be much more effective at lowering blood sugar following supper. The evening meal, often the largest of the day, can significantly raise 24-hour glucose levels.
The innovative exercise science study was conducted at the Clinical Exercise Physiology Laboratory at the George Washington University School of Public Health and Health Services (SPHHS) using whole room calorimeters. Loretta DiPietro, Ph.D., chair of the SPHHS Department of Exercise Science, led the study.
"These findings are good news for people in their 70s and 80s who may feel more capable of engaging in intermittent physical activity on a daily basis," DiPietro said in a press release.
Putting Humans in a Box to Measure Their Energy Use
The whole room calorimeter (WRM), which looks like a very small hotel room, is a controlled-air environment for human study that allows scientists to calculate a person's energy expenditure by testing samples of air. The balance of oxygen consumed and carbon dioxide produced varies according to the activity level of the person in the room. The WRM also measures the body’s use of different food fuels, such as carbohydrates, proteins, and fats.
The 10 study participants spent three 48-hour periods in the small calorimeter rooms. Each room was equipped with a bed, toilet, sink, treadmill, television, and computer, leaving little room to move around.
Participants ate standardized meals, and their blood sugar levels were monitored continuously using blood tests.
The first day in the WRM served as a control period, with no exercise. On the second day, participants either walked at a moderate pace on the treadmill for 15 minutes after each meal, or for 45 minutes in either the late morning or before supper.
The researchers observed that the evening post-meal walk was the most effective in lowering blood sugar levels for a full 24 hours.
The typical exaggerated rise in blood sugar after supper—which often lasts well into the night and early morning—was curbed significantly as soon as the participants started to walk on the treadmill, the study authors said.
How Age Affects Insulin Resistance
An estimated 79 million Americans have pre-diabetes, according to the National Diabetes Education Program run by the National Institutes of Health. But many people have no idea they are at risk.
According to DiPietro, older people may be particularly susceptible to poor blood sugar control after meals because inactive muscles contribute to insulin resistance. The problem is compounded by slow or low insulin secretion by the pancreas, which often occurs as the body ages.
“Post-meal high blood sugar is a key risk factor in the progression from impaired glucose tolerance (pre-diabetes) to type 2 diabetes and cardiovascular disease,” DiPietro explained.
Other studies have suggested that weight loss and exercise can prevent type 2 diabetes. The authors say theirs is the first study to examine short bouts of physical activity timed around the risky period following meals—a time when blood sugar can rise rapidly and potentially cause damage to internal organs and blood vessels.
"The muscle contractions connected with short walks were immediately effective in blunting the potentially damaging elevations in post-meal blood sugar commonly observed in older people," DiPietro said.
If the findings of this small study hold up to further testing, it could lead to an inexpensive prevention strategy for pre-diabetes, which can develop over time into type 2 diabetes.
Back in the day, it was “de rigueur” to take a morning, noon, and evening walk. The time has come to get up from the table, tie on those walking shoes, and take a little stroll around the block.