Metabolic implications when employing heavy pre- and post-exercise rapid-acting insulin reductions to prevent hypoglycaemia in type 1 diabetes patients: A randomised clinical trial

Abstract

Aim: To examine the metabolic, gluco-regulatory-hormonal and inflammatory cytokine responses to large reductions in rapid-acting insulin dose administered prandially before and after intensive running exercise in male type 1 diabetes patients. Methods: This was a single centre, randomised, controlled open label study. Following preliminary testing, 8 male patients (2462 years, HbA1c 7.760.4%/6164 mmol.l21) treated with insulin's glargine and aspart, or lispro attended the laboratory on two mornings at ,08:00 h and consumed a standardised breakfast carbohydrate bolus (1 g carbohydrate.kg21BM; 380610 kcal) and self-administered a 75% reduced rapid-acting insulin dose 60 minutes before 45 minutes of intensive treadmill running at 73.160.9% VO2peak. At 60 minutes post-exercise, patients ingested a meal (1 g carbohydrate.kg21BM; 660621 kcal) and administered either a Full or 50% reduced rapid-acting insulin dose. Blood glucose and lactate, serum insulin, cortisol, non-esterified-fatty-acids, b-Hydroxybutyrate, and plasma glucagon, adrenaline, noradrenaline, IL-6, and TNF-a concentrations were measured for 180 minutes post-meal. Results: All participants were analysed. All glycaemic, metabolic, hormonal, and cytokine responses were similar between conditions up to 60 minutes following exercise. Following the post-exercise meal, serum insulin concentrations were lower under 50% (p,0.05) resulting in 75% of patients experiencing hyperglycaemia (blood glucose $8.0 mmol.l21; 50% n=6, Full n = 3). b-Hydroxybutyrate concentrations decreased similarly, such that at 180 minutes post-meal concentrations were lower than rest under Full and 50%. IL-6 and TNF-a concentrations remained similar to fasting levels under 50% but declined under Full. Under 50% IL-6 concentrations were inversely related with serum insulin concentrations (r = 20.484, p = 0.017). Conclusions: Heavily reducing rapid-acting insulin dose with a carbohydrate bolus before, and a meal after intensive running exercise may cause hyperglycaemia, but does not augment ketonaemia, raise inflammatory cytokines TNF-a and IL- 6 above fasting levels, or cause other adverse metabolic or hormonal disturbances. Trial Registration: ClinicalTrials.gov NCT01531855. © 2014 Campbell et al. This.