Summary

Little is known of how reduced exercise affects metabolism. In a study on healthy young volunteers, cutting down the daily number of steps taken had a surprisingly rapid impact on insulin sensitivity and deposition of abdominal fat, suggesting it is vital to keep up a regular routine.

Introduction

The benefits of regular daily exercise on physical and mental health are well known. Rather less is understood on how metabolic measures, like blood glucose levels or lipid profile, change with increases or decreases in physical activity. These changes can often signal the start of disease like diabetes or heart problems long before any symptoms. Insulin resistance, in particular, can be an early sign of diabetes.

Walking is one of the simplest and most effective form of exercise. Research has suggested that doing 10,000 steps or more a day can improve blood pressure, weight, and achieve other benefits. It's easy to reach this goal using a reliable pedometer as a companion, and you do not need to do all the steps in one go - you can fit them into your daily routine. But what if, for some reason, you reduce your daily steps? Researchers at the University of Copenhagen carried out a study to find out what impact this has on metabolic measurements and how it might influence future health prospects.

What was done

The study was done in two parts with participants being advised to do the opposite of what is normally recommended to reduce their daily steps. They were to take elevators instead of stairs, and ride in cars instead of walking or cycling. They used a reliable pedometer to record their daily steps. The first group, consisting of eight men, reduced their daily steps from an average value of 6203 to 1394. The second group, consisting of ten men, reduced their daily steps from an average of 10,501 to 1344. The researchers carried out an oral glucose tolerance test in the first group at the start and then on days 7, 14 and 22. The same test was done at day 14 with the second group. They also carried out measures of triglycerides, oral fat tolerance, insulin and intra-abdominal fat.

What was found

Analysis of the lab tests showed metabolic changes occurred suggestive of insulin resistance and there was also a small increase in intra-abdominal fat.

What this study means

The researchers suggest that when stepping rates are reduced, calories that would be used to maintain muscle go instead to deposit fat in the abdominal area. At the same time, glucose and fat are handled less efficiently by metabolic processes. These participants were healthy, but just a few days of reduced exercise were enough to start off metabolic changes which, if prolonged, could lead to disease. The body knows, and responds, when you slack off your daily exercise routine, but it may take much longer for these changes to translate into symptoms of disease. Therefore, it's important to make exercise regular and daily is best.