This article is more than 5 years old. Information may no longer be current.
Prandial reduction of insulin, low-glycemic index meal may prevent exercise-induced hypoglycemia
Click Here to Manage Email Alerts
In patients with type 1 diabetes, the combined use of a basal-bolus insulin reduction and a low-glycemic index feeding strategy may be effective in preventing exercise-induced hypoglycemia without inducing hyperglycemia, according to recent findings.
In a randomized controlled trial, researchers evaluated 10 male patients (mean age, 27 ± 2 years; type 1 diabetes duration, 12 ± 2 years). Participants had HbA1c levels of 6.9 ± 0.2%, and all were on a basal-bolus regimen consisting of glargine (n = 8) or detemir (n = 2) long-lasting insulin, as well as rapid-acting insulin aspart. Participants had been stable on these regimens for at least 1 year.
All participants were fitted with continuous glucose monitoring and completed two randomized study-days separated by 1 week, during which daily basal insulin dose was either unaltered (the 100% group) or decreased by 20% (the 80% group). Patients took a morning fasted blood sample, ate standardized meals as dictated by the researchers and received a 75% decreased rapid-acting insulin dose after the evening meal. An hour later, the participants completed 45 minutes of running on a treadmill followed by intake of a low-glycemic index meal. The participants received a 50% decreased rapid-acting dose of insulin after exercise, and consumed a low-glycemic index snack before bedtime. On the day after exercise, participants given 80% of their total insulin dose were returned to their full doses.
The researchers assayed blood samples taken for glucose, glucoregulatory hormones, non-esterified fatty acids, beta-hydroxybutyrate, interleukin-6, and tumor necrosis factor-alpha levels.
Participants’ interstitial glucose levels were monitored for 24 hours before exercise and 24 hours after exercise.
They found comparable glycemia up to 6 hours after exercise in both groups of patients, with no events of hypoglycemia. In the group whose dosages were unchanged, glucose levels fell after 6 hours, with nine participants experiencing nighttime hypoglycemia. In contrast, during the period in which 80% of insulin dosages were administered, no participants experienced nocturnal hypoglycemia, and were protected from this for 24 hours after exercise. Patients in the 80% group spent less time in a hypoglycemic state (P < .001), with more time spent at normal blood glucose levels (397 ± 56 minutes vs. the 100% group, 122 ± 28 minutes; P < .001). The next day, the 80% group had more typical blood glucose levels upon waking and before exercise (P > .05). Tumor necrosis factor-alpha levels were normal in both groups.
“This is the first study to demonstrate that exercise-induced hypoglycemia can be avoided, without exposure to hyperglycemia, when people with type 1 diabetes employ a combined basal-bolus insulin reduction and low-[glycemic index] carbohydrate feeding strategy,” the researchers wrote.
“Effectively managing the risk of hypoglycemia and normalizing glycemia following exercise is critical for safe, long-term exercise adherence, and potentially improvements in wider diabetes management,” the researchers concluded. – by Jennifer Byrne
Disclosure: This study was funded by the Northumbria University Strategic Investment Fund. The researchers report no relevant financial disclosures.
Perspective
Back to Top
Sheri R. Colberg, PhD, FACSM
In their latest study, Campbell and his colleagues attempt to address a very valid concern in adults with type 1 diabetes using a basal-bolus insulin injection regimen, namely how to prevent overnight hypoglycemia after a single bout of moderate intensity, continuous aerobic exercise. Fear of hypoglycemia is a key reason why many people with type 1 diabetes choose to avoid exercise or why they only undertake it earlier in the day. Being able to fit exercise in on a daily basis often requires greater flexibility with its timing and, unfortunately, evening exercise frequently results in severe hypoglycemia during sleep for those who have undertaken it. By combining modest reductions in basal doses (glargine or levemir) of only 80% with larger reductions in pre-exercise and post-exercise meal short-acting insulin doses to cover carbohydrates, these researchers demonstrated that insulin reductions—combined with intake of carbohydrates that are more slowly absorbed post-exercise—prevent not only overnight lows, but also hyperglycemia that can result from food taken to prevent later-onset lows. While we definitely need more studies along the lines of this one to address all the factors that can impact glycemic control around evening exercise, it is a great start for adding to what we know about making appropriate regimen changes to prevent overnight hypoglycemia caused by exercise while maintaining euglycemia.
Click Here to Manage Email Alerts