Timing of insulin suspension pre-exercise affects hypoglycemia risk
medwireNews: Reducing basal insulin in people with type 1 diabetes by 50–80% 90 minutes before exercise results in significantly smaller falls in blood glucose than suspending insulin at exercise onset, shows research presented at ADA’s 78th Scientific Sessions in Orlando, Florida.
When the 17 participants of the OmniTIME study suspended their insulin pump delivery immediately prior to a moderate-to-highly active aerobic exercise session (walking at approximately 50% VO2 max for 60 minutes), their blood glucose level fell by an average 67 mg/dL (3.7 mmol/L) from a baseline level of 164 mg/dL (9.1 mmol/L).
This reduction was significantly greater than that seen when the same participants reduced their basal insulin by 50% and 80% 90 minutes before exercise. Under these two experimental conditions, the reductions in blood glucose were 47 mg/dL (2.6 mmol/L) and 31 mg/dL (1.7 mmol/L), respectively, from baseline levels of 191 mg/dL (10.6 mmol/L) and 164 mg/dL (9.1 mmol/L). The difference between the 50% and 80% settings was also statistically significant.
During the exercise challenge, the rate of hypoglycemic events was significantly higher when insulin was stopped immediately prior to initiation than when it was reduced 90 minutes earlier, at 41% versus 6% with both the 50% and 80% insulin reductions.
Basal insulin rates were resumed immediately after exercise and Dessi Zaharieva, from York University in Toronto, Ontario, Canada, noted that blood glucose was relatively stable among all conditions following a meal challenge and subsequently overnight. There were also no cases of pre-exercise hyperglycemia when insulin was reduced 90 minutes before exercise.
However, Zaharieva pointed out that there was a wide range of baseline blood glucose values, which means that “we can’t make a blanket statement to all individuals with type 1 diabetes.”
She added: “There needs to be individual changes and it might take a little bit of practice with each participant […] to make it work.”
Zaharieva told medwireNews that future research needs to focus on exercise in type 1 diabetes as not enough has been done in the past.
She said that many people are afraid to exercise due to a fear of hypoglycemia, so “we need to be getting this out there that it is possible to exercise, we just maybe need to be doing a little bit more preplanning and looking at this study in more detail.”
By Laura Cowen
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