Glycemic management for young people with type 1 diabetes may not be negatively affected by carbohydrate intake before exercise that includes intermittent sprints, according to findings published in Diabetic Medicine.
“Carbohydrate ingestion before, during and after exercise can reduce the hypoglycemia risk associated with both planned and unplanned physical activities. Another effective means to reduce hypoglycemia risk during moderate exercise is to incorporate repeated short sprints in a pattern of activity referred to as intermittent high-intensity exercise,” W.H.K. Soon, PhD, a research assistant at the Telethon Kids Institute in West Perth, Australia, and colleagues wrote. “These findings raise the issue of whether the pre-exercise ingestion of carbohydrates at levels recommended to maintain stable glycemia during moderate-intensity exercise might result in an excessive rise in blood glucose level if combined with repeated sprints.”
Soon and colleagues recruited eight participants aged 14 to 35 years (mean age, 18.8 years; five females; mean HbA1c, 61 mmol/L; mean BMI, 25.9 kg/m2) from the Princess Margaret Hospital diabetes clinic in Perth, Australia, to measure blood glucose response during and after four separate exercise routines. These routines were completed in a random order on 4 separate days. Participants fasted overnight and took morning insulin before exercise.
The first routine was moderate-intensity exercise of 40 minutes of cycling at 50% peak oxygen consumption. The second was intermittent high-intensity exercise of 40 minutes of cycling at 50% peak oxygen consumption with interspersed sprints every 2 minutes and a 10-second sprint at the conclusion. The third was the moderate-intensity exercise after the ingestion of 3.5 mg carbohydrates per hour of exercise. The final routine was the high-intensity exercise after the same carbohydrate intake.
During each exercise, blood glucose response was measured by time-averaged area under the blood glucose curve and by peak blood glucose level during each exercise. Participants were measured for blood glucose, lactate and heart rate at zero, 10, 20, 30 and 40 minutes after exercising.
The researchers found significant differences in time-averaged blood glucose AUC when comparing moderate exercise vs. moderate exercise with carbohydrate intake (–1.7 mmol/L; 95% CI, –2.6 to –0.8), moderate exercise vs. intense exercise with carbohydrate intake (–1.5 mmol/L; 95% CI, –2.4 to –0.5), moderate exercise with carbohydrate intake vs. intense exercise (1.5 mmol/L; 95% CI, 0.5-2.4) and intense exercise vs. intense exercise with carbohydrate intake (–1.3 mmol/L; 95% CI, –2.2 to –0.3).
However, no significant differences in mean time-averaged blood glucose AUC and peak blood glucose levels were found when comparing moderate exercise with carbohydrate intake and exercise that included both intermittent sprints and pre-routine carbohydrate consumption. The same was true when comparing the time-averaged blood glucose AUC and peak blood glucose level between the non-carbohydrate moderate-exercise and intense-exercise routines. In addition, blood glucose levels were elevated for at least 30 minutes after both pre-carbohydrate exercises.
“Against expectations, the present study showed that when carbohydrates were ingested prior to moderate-intensity exercise in the fasted state under basal insulin conditions, there was no evidence to suggest that adding repeated sprints caused any further significant increase in blood glucose levels during and after exercise,” the researchers wrote. – by Phil Neuffer
Disclosures: The authors report no relevant financial disclosures.