Judith Regensteiner, Ph.D., led discussion on physical activity
and metabolic health. The subcommittee focused on the following research
questions:
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What is the relationship between physical activity and
prevention of metabolic syndrome/insulin resistance?
Conclusions
There is an inverse dose-response association between physical activity level
(and fitness) and the development of metabolic syndrome in adults. The minimal
amount of activity ranges between 120 – 180 minutes per week of moderate
intensity physical activity; however, many studies support 150 minutes per week.
The pattern is similar in men and women but there is a need for more data
examining metabolic syndrome in youth and across ethnicities.
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What is the relationship between physical activity and
prevention and treatment of Type 2 Diabetes (T2DM)?
Conclusions
There is strong RCT data as well as observational, longitudinal, cross-sectional
data and meta-analyses. The data presents strong evidence that physical activity
has a major role in the prevention of T2DM and is consistent in both men and
women. The data also suggests that 30 minutes per day of moderate intensity
exercise appears to be an effective dose although it is not entirely clear. The
independent role of physical activity in the prevention of T2DM as well as the
effects across different ethnic groups is not clear.
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What is the relationship between physical activity and
prevention of macrovascular complications of T2DM?
Conclusions
The group interpreted longitudinal, cross-sectional and observational studies as
well as 1 meta-analysis. From the data it appears exercise is particularly
beneficial for reducing cardiovascular risks. Dose-response studies suggest at
least 2 hours per week of moderate exercise is required for significant
benefits. The benefit may reach a peak level at 3 – 7 hours; however, more hours
show a flattening of benefit. The studies also seem to support a recommendation
of moderately vigorous exercise. Aerobic or combined aerobic/resistance exercise
seem best. There may be differences in the dose-response between genders but
more study is required. There is no data on ethnic differences.
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What is the relationship between physical activity and Type 1 Diabetes?
Conclusions
There is no evidence that physical activity helps prevent Type 1 Diabetes. There
are many small interventional studies; however, they are split on whether
physical activity has benefits. The most positive results show modest
improvement. The results are also mixed on glycemic control and there is no
dose-response data. It is likely that the recommendations for Type 1 Diabetes
are similar to Type 2; however, additional precautions are needed to prevent
hypoglycemia during exercise and recovery.
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What is the relationship between physical activity and microvascular
complications of diabetes?
Conclusions
There is fair evidence to support conclusions in this area. It is very likely
physical activity reduces the risk of diabetic neuropathy and likely it reduces
the risks of diabetic nephropathy. It is neither likely nor unlikely to reduce
diabetic retinopathy in Type 1 Diabetes and there is no data on Type 2 Diabetes.
There is poor evidence surrounding the benefits of physical activity and the
treatment of microvascular complications.
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What is the relationship between physical activity and
gestational diabetes?
Conclusions
There are some observational studies that suggest physical activity is
beneficial in preventing gestational diabetes but there are no RCTs to support
this conclusion. Overall the data suggests approximately 30 minutes per day of
moderate intensity activity reduces the risk.