How to prescribe weight lifting exercise for diabetes
The benefits of PRT are related to both acute alterations in
insulin sensitivity as well as chronic body composition adaptations
(increased muscle and decreased visceral, hepatic, intramuscular,
and whole body fat depots).39 As the acute effect is most
prominent in the 48 hours after an exercise bout, it is
recommended that PRT be undertaken three days per week for
metabolic control (with at least one day of rest between training
for muscle recovery and hypertrophy). Engagement of most major
muscle groups (eight to ten different weightlifting exercises) is
best for metabolic and functional benefits, and should take about
30 to 45 minutes to complete two to three sets of eight repetitions.
Most successful trials43 have used moderate-to-high intensity
training (lifting about 60-80% of the maximum weight possible for
a given exercise, or an 8-to-10 repetition maximum, then
progressively increasing the load as strength is gained). This is the
same PRT prescription that benefits the other co-morbidities
prevalent in type 2 diabetes (see Figure 2) and in older adults for
other chronic conditions (see Table 2), thus providing a single,
economical exercise foundation for such individuals. However,
aerobic exercise provides benefits complementary and in some
cases superior to PRT,44 such as improved cardiovascular fitness,
peripheral vascular disease symptoms, and other metabolic
functions such as fat oxidation and reduced inflammation. Thus, a
combination of PRT and aerobic exercise in older adults, as
recommended by the American College of Sports Medicine and
others, is theoretically optimal for disease prevention, and
combined aerobic and resistance training is superior for changes
in HbA1c, but not for any other metabolic, cardiovascular,
musculoskeletal, or body composition outcomes compared to
uni-modal exercise, despite double the volume of exercise.44