HERNANDEZ, J. M., T. MOCCIA, J. D. FLUCKEY, J. S. ULBRECHT, and P. A. FARRELL. Fluid snacks to help persons with type 1 diabetes avoid late onset postexercise hypoglycemia. Med. Sci. Sports Exerc., Vol. 32, No. 5, pp. 904–910, 2000.
Purpose: The present study assessed whether whole milk, skim milk, or two commercially available sports drinks are effective in preventing late onset postexercise hypoglycemia (LOPEH) in persons with type 1 diabetes mellitus.
Methods: Subjects ingested water, whole milk, skim milk, sport drink A(carbohydrate and electrolytes), or sport drink B (carbohydrate, fat, and protein) before, during, and after 1 h of bicycle exercise at 60% V̇O2max in the late afternoon. Drinks were isocaloric (470 ± 150 kcal) and the number of calories consumed was based on individual energy expenditure. No adjustment in insulinization was allowed in anticipation of exercise.
Results: During water trials all subjects became hypoglycemic. Most drinks lead to a moderate hyperglycemia(range of mean values = 200–280 mg·dL−1) during the period between the end of exercise and dinner, but this was not the case for whole milk(range 80–120 mg·dL−1). Glycemia peaked about 1.5 h after dinner and declined over the next 90 min. Persistent hyperglycemia (range of means = 200–310 mg·dL−1) from after exercise to about 4 h postexercise was observed with sports drink B. A decline in glycemia in the evening was greatest during the skim milk trial and required subjects to ingest more carbohydrate as a late evening snack. The least decline during this period occurred during the whole milk trial. Subjects experienced pre-bed and early morning (0300 h) hypoglycemia in 7 of the 28 trials.
Conclusions: These data show that whole milk and sports drinks that are designed for both quick (sport drink A) and long lasting (sport drink B) nutrient replenishment can be used by persons with type 1 diabetes in an effort to avoid LOPEH.
A potential outcome of exercise for persons with type 1 diabetes mellitus is exercise-induced hypoglycemia, which may occur during, immediately after, or several hours after exercise. During prolonged moderate intensity exercise, the normal reduction of plasma insulin concentration observed in nondiabetic individuals (4,7,9) cannot take place in persons with type 1 diabetes, thus decreasing hepatic glucose production and consequently the increased demand for glucose by the working muscle cannot be met (9). A high incidence of late onset postexercise hypoglycemia (LOPEH) was reported by MacDonald (15) in individuals with type 1 diabetes who exercised on a regular basis. Late onset postexercise hypoglycemia was defined as hypoglycemia occurring more than 4 h after exercise, and in that study LOPEH usually occurred 6–14 h after exercise. The incidence of LOPEH might be increased in well-controlled diabetic individuals since these patients can have high insulin levels and normal or near normal blood glucose before exercise (17). Thus LOPEH may become more of a clinical problem as a result of the DCCT (8,23) recommendations that encourage tight glucose control. To date, no studies have been reported on the incidence of LOPEH in patients using the latest recommendations of the DCCT concerning Multiple Daily Injection (MDI) Regimens.
A reduction of the pre-exercise insulin dose and an increase in the caloric content of the pre-exercise meal have been recommended for the prevention of exercise-induced hypoglycemia in IDDM (6,10,14). These recommendations are helpful for avoiding hypoglycemia during and in the immediate postexercise period; however, little information is available concerning the type, amount, and timing of exercise snacks for the purpose of avoiding LOPEH.
Theoretically, the “ideal” snack should supply adequate but not excessive calories to compensate for elevated metabolism of the working muscle during and after exercise. Also, the digestion and absorption of the carbohydrate content of the snack (glycemic response) should be just fast enough to prevent hypoglycemia without producing hyperglycemia. Nathan et al. (16) investigated the effect of a 13-g carbohydrate snack in the form of orange juice, skim milk, or whole milk versus water (placebo) on glycemia during and for 2 h after 45 min of moderate exercise in persons with type 1 diabetes. Exercise was conducted in the morning after an overnight fast. All drinks prevented decreases in glycemia (in most of the subjects) when compared with water during exercise and for 90 min postexercise. Whole milk seemed to maintain euglycemia better than the other drinks, and Nathan et al. (16) proposed whole milk as an appropriate pre-exercise snack for individuals with type 1 diabetes who wish to engage in moderate exercise. Nathan’s study could not provide information on the effectiveness of these drinks in helping to avoid LOPEH.
A large number of studies have reported the effectiveness of various sports drinks in helping to maintain euglycemia during prolonged exercise in nondiabetic subjects. These drinks include mixtures of carbohydrate and electrolytes or more nutritionally complete mixtures that contain fat and protein, with the latter being intended as diet supplements rather than immediate sources of carbohydrates. Since sports drinks are readily available and could be used by persons with type 1 diabetes to help avoid hypoglycemia, the present study was designed to determine whether whole milk and skim milk, as well as selected commercially available liquid snacks, are effective in preventing LOPEH.
Noll Physiological Research Center and Center for Locomotion Studies, The Pennsylvania State University, University Park, PA 16802
Submitted for publication October 1998.
Accepted for publication June 1999.
Address for correspondence: Peter A. Farrell, Ph.D., Noll Physiological Research Center, University Park, PA 16801.