Prolonged exercise in type 1 diabetes: performance of a customizable algorithm to estimate the carbohydrate supplements to minimize glycemic imbalances

Physical activity in patients with type 1 diabetes (T1DM) is hindered because of the high risk of glycemic imbalances. A recently proposed algorithm (named Ecres) estimates well enough the supplemental carbohydrates for exercises lasting one hour, but its performance for prolonged exercise requires validation. Nine T1DM patients (5M/4F; 35-65 years; HbA1c 54 \ub1 13 mmol \ub7 mol(-1)) performed, under free-life conditions, a 3-h walk at 30% heart rate reserve while insulin concentrations, whole-body carbohydrate oxidation rates (determined by indirect calorimetry) and supplemental carbohydrates (93% sucrose), together with glycemia, were measured every 30 min. Data were subsequently compared with the corresponding values estimated by the algorithm. No significant difference was found between the estimated insulin concentrations and the laboratory-measured values (p = NS). Carbohydrates oxidation rate decreased significantly with time (from 0.84 \ub1 0.31 to 0.53 \ub1 0.24 g \ub7 min(-1), respectively; p < 0.001), being estimated well enough by the algorithm (p = NS). Estimated carbohydrates requirements were practically equal to the corresponding measured values (p = NS), the difference between the two quantities amounting to -1.0 \ub1 6.1 g, independent of the elapsed exercise time (time effect, p = NS). Results confirm that Ecres provides a satisfactory estimate of the carbohydrates required to avoid glycemic imbalances during moderate intensity aerobic physical activity, opening the prospect of an intriguing method that could liberate patients from the fear of exercise-induced hypoglycemia

Oxidative Stress in Patients with Type 1 Diabetes Mellitus: Is It Affected by a Single Bout of Prolonged Exercise?

Presently, no clear-cut guidelines are available to suggest the more appropriate physical activity for patients with type 1 diabetes mellitus due to paucity of experimental data obtained under patients' usual life conditions. Accordingly, we explored the oxidative stress levels associated with a prolonged moderate intensity, but fatiguing, exercise performed under usual therapy in patients with type 1 diabetes mellitus and matched healthy controls. Eight patients (4 men, 4 women; 49\ub111 years; Body Mass Index 25.0\ub13.2 kg\ub7m-2; HbA1c 57\ub110 mmol\ub7mol -1) and 14 controls (8 men, 6 women; 47\ub111 years; Body Mass Index 24.3\ub13.3 kg\ub7m-2) performed a 3-h walk at 30% of their heart rate reserve. Venous blood samples were obtained before and at the end of the exercise for clinical chemistry analysis and antioxidant capacity. Capillary blood samples were taken at the start and thereafter every 30 min to determine lipid peroxidation. Patients showed higher oxidative stress values as compared to controls (95.9\ub19.7 vs. 74.1\ub112.2 mg\ub7L -1 H2O2; p<0.001). In both groups, oxidative stress remained constant throughout the exercise (p = NS), while oxidative defence increased significantly at the end of exercise (p<0.02) from 1.16\ub10.13 to 1.19\ub10.10 mmol\ub7L-1 Trolox in patients and from 1.09\ub10.21 to 1.22\ub10.14 mmol\ub7L -1 Trolox in controls, without any significant difference between the two groups. Oxidative stress was positively correlated to HbA1c (p<0.005) and negatively related with uric acid (p<0.005). In conclusion, we were the first to evaluate the oxidative stress in patients with type 1 diabetes exercising under their usual life conditions (i.e. usual therapy and diet). Specifically, we found that the oxidative stress was not exacerbated due to a single bout of prolonged moderate intensity aerobic exercise, a condition simulating several outdoor leisure time physical activities. Oxidative defence increased in both patients and controls, suggesting beneficial effects of prolonged aerobic fatiguing exercis

Whole-body glucose oxidation rate during prolonged exercise in type 1 diabetic patients under usual life conditions

Objective Fuel oxidation during exercise was studied in type 1 insulin-dependent (T1DM) patients mainly under quite constant insulin and glycemia; these protocols, however, likely do not reflect patients' usual metabolic conditions. The glucose oxidation rate (GLUox) in T1DM patients under usual life conditions was thus investigated during prolonged exercise (3-h) and its behavior was described mathematically. Materials/Methods Whole-body GLUox was determined in eight T1DM patients (4/8 M; aged 35-59 years) and eight well-matched healthy subjects. Venous blood was drawn prior to and every 30 min until the end of exercise; glycemia, insulin, cortisol, and growth hormone concentrations were determined. Oxygen consumption, carbon dioxide production, and ventilation were measured at rest and thereafter every 30 min of the exercise. To prevent hypoglycemia, patients were given fruit fudge (93% sucrose) prior to / during exercise. Results Insulin concentration and glycemia were significantly higher in patients across the entire exercise period (group effect, p < 0.001 for both). GLUox decreased significantly with increasing exercise duration (time effect, p < 0.001), but no significant difference was detected between the two groups (group effect, p = NS). GLUox, expressed as the percentage of the starting value, was described by an exponential function showing a time constant of 90 min (n = 96; mean corrected R2 = 0.666). Conclusions GLUox in T1DM patients was not significantly different from the rate observed in the control subjects. The function describing the time course of GLUox may be useful to correct an estimated GLUox for the duration of exercise and help T1DM patients avoiding exercise-induced glycemic imbalances

Sex differences in hydration status among adolescent elite soccer players

Hydration of athletes may affect performance and health status likely with differences among sexes. We studied the impact of sex on hydration behaviour in adolescent athletes. Hydration status and urine markers were investigated in 7 female and 7 male elite 16 years-old soccer players in temperate climate (21-24°C). Participants consumed water ad libitum during the first training session (LIB), whereas in the second session (HYD) they drunk a water amount matching 70% of sweat loss from the LIB session. Post-training performances were evaluated by Yo-Yo intermittent recovery level 1 (IR1) test and countermovement jump (CMJ). Body mass values were recorded and urine samples were collected before and after each experimental session. Males drunk a double amount of water in HYD (1.19±0.21 kg) compared to LIB (0.62±0.19 kg; p=0.001; ES=2.88), resulting in a lower percentage body mass loss (HYD -0.95±0.63% versus LIB -1.59±0.33%; p=0.044; ES=-1.35); total distance of Yo-Yo IR1 was higher, albeit not significantly, in HYD (2953±779 m) than in LIB (2103±939 m); CMJ performance was unchanged. In females, water drunk, body mass, Yo-Yo IR1 and CMJ did not vary in HYD versus LIB sessions. In adolescent males a 70% sweat replacement personalized hydration regimen reduced body mass loss and tended to improve performance, whereas in females ad libitum water drinking allowed to maintain hydration status (<1% body mass loss). Our results suggest that coaches and athletes themselves should consider a personalized hydration regimen for adolescent male soccer players, whereas ad libitum drinking seems suitable for females

Association of recreational physical activity with homocysteine, folate and lipid markers in young women

Eur J Appl Physiol. 2009 Jan;105(1):111-8. Epub 2008 Oct 14. Association of recreational physical activity with homocysteine, folate and lipid markers in young women. Di Santolo M, Banfi G, Stel G, Cauci S. SourceDepartment of Biomedical Sciences and Technologies, School of Medicine, University of Udine, 33100, Udine, Italy. Abstract We assessed the influence of recreational physical activity in young healthy women on homocysteine, a potential risk factor for cardiovascular disease (CVD). Participants were 124 23-year-old normal-weight Italian recreational athletes (performing 8.7 +/- 2.46 h week(-1) exercise) and 116 controls. Median blood homocysteine, folate and lipid markers did not differ between athletes and controls. Elevated homocysteine levels at CVD risk > or =12.0 and > or =15.0 micromol l(-1) were not different between groups. Continuous homocysteine was inversely related to folate (P or =15.0 micromol l(-1). Recreational physical exercise does not adversely impact homocysteine levels among young women. Only low folate significantly increases the risk for hyperhomocysteinemia in young women

Gender Differences in Hydration Status of Adolescent Soccer Players After Training Sessions

6nonenoneIlaria, Venuto; BUOITE STELLA, ALEX; STEL, Giuliana; Saulle, Mazzolini; FRANCESCATO, Maria Pia; CAUCI, SabinaIlaria, Venuto; BUOITE STELLA, Alex; Stel, Giuliana; Saulle, Mazzolini; Francescato, Maria Pia; Cauci, Sabin

Demographic, clinical, and baseline biochemical parameters of the study subjects.

<p>Values are expressed as means ±SD. Parameters failing normal distribution (^§) are shown as median value and range (in brackets) and the Mann-Whitney U test was used to test their statistically significant differences.</p

Relationship between oxidative stress and HbA_1c or uric acid.

<p>Panel A. Relationship between baseline HbA_1c values (mmol·mol⁻¹) and oxidative stress (mg·L⁻¹ H₂O₂). The relationship is statistically significant (n = 20, R = 0.649, p<0.005). Panel B. Relationship between baseline uric acid values (mg·dL⁻¹) and oxidative stress (mg·L⁻¹ H₂O₂). The relationship is statistically significant (n = 22, R = 0.621, p<0.005). In both panels: full dots = patients with type 1 DM, open dots = healthy control subjects, dotted lines = 95% confidence limits.</p

Relationship between insulin concentrations estimated by the <i>Ecres</i> algorithm and the corresponding laboratory-measured values.

<p>The relationship between estimated and measured insulin concentrations was statistically significant (R = 0.771, p < 0.001, n = 81). Dashed lines are the 95% Confidence Limits. Dashed-dotted line is the identity line.</p