Increased cardiorespiratory fitness improves glucose tolerance in
overweight individuals, but no evidence shows this relationship to be
independent of weight loss. Evidence Category C.
Rationale: Two RCTs
that examined the effects of weight loss on glucose tolerance in older men (369) and in persons with diabetes (404) also had measures of VO2
max (oxygen consumption) as a measure of fitness. In both studies,
physical activity resulted in a net weight loss of approximately 2.3 to 2.5 kg
(2 to 3 percent) and increased VO2 max by 9 to 18
percent. In one study (419) most measures of
glucose tolerance improved, whereas in the other study (369)only 2 hour insulin improved. Neither study
was designed to test whether increased fitness improves glucose tolerance
independent of weight loss.
|Recommendation: Weight loss is recommended to lower
elevated blood glucose levels in overweight and obese persons with type 2
diabetes. Evidence Category A.