Couch Potatoes, Even if They Exercise, Develop Insulin Resistance

People who spend a lot of time in a sedentary phase, whether work- or leisure-related, are likely to develop insulin resistance, which is a stepping stone to type 2 diabetes.  British Medical Research Council scientists have done a study to see whether such people can compensate for this by increasing their non-sedentary-time exercise level.  The results are published in the journal Diabetes. 

A group of 376 middle-aged men and women were followed for 5½ years. Physical activity and sedentary time were measured at baseline and follow-up using individual minute-by-minute heart rate monitoring.  Sedentary time was calculated from heart rate observations below an individually determined threshold, and was described as a percentage of total monitored time during the waking hours of 4 days.  Moderate or vigorous physical activity was defined as the percentage time spent above 1.75 times the resting heart rate.  Fasting plasma insulin levels were measured as an indirect identification of insulin resistance.

Time spent sedentary at baseline was significantly associated with fasting insulin levels at follow-up, i.e. several years later.  This association was independent of age, gender, fasting insulin at baseline, fat mass at baseline, and smoking status.  More importantly, the time spent in moderate or vigorous exercise was without influence on the association.

These findings strongly suggest that efforts to make people exercise more will be without benefit on threatened insulin resistance, except insofar that they result in less sedentary time.  And, as we all know, reducing sedentary time at home is often quite fruitless.  So increased exercise must be scheduled to replace sedentary time.  I suggest getting a dog that needs a lot of exercise.