Ausdauer-Leistungsfähigkeit von Triathlon-Athleten mit Typ-1-Diabetes

The Effect of Starting Blood Glucose Levels on Serum Electrolyte Concentrations during and after Exercise in Type 1 Diabetes

Fear of hypoglycemia is a major exercise barrier for people with type 1 diabetes (PWT1D). Consequently, although guidelines recommend starting exercise with blood glucose (BG) concentration at 7-10 mmol/L, PWT1D often start higher, potentially affecting hydration and serum electrolyte concentrations. To test this, we examined serum and urine electrolyte concentrations during aerobic exercise (cycling 45 min at 60%VO₂peak) in 12 PWT1D (10F/2M, mean ± SEM: age 29 ± 2.3 years, VO₂peak 37.9 ± 2.2 mL·kg^-1·min^-1) with starting BG levels: 8-10 (MOD), and 12-14 (HI) mmol/L. Age, sex, and fitness-matched controls without diabetes (CON) completed one exercise session with BG in the normal physiological range. Serum glucose was significantly higher during exercise and recovery in HI versus MOD (p = 0.0002 and p < 0.0001, respectively) and in MOD versus CON (p < 0.0001). During exercise and recovery, MOD and HI were not significantly different in serum insulin (p = 0.59 and p = 0.63), sodium (p = 0.058 and p = 0.08), potassium (p = 0.17 and p = 0.16), calcium (p = 0.75 and 0.19), and magnesium p = 0.24 and p = 0.09). Our findings suggest that exercise of moderate intensity and duration with higher BG levels may not pose an immediate risk to hydration or serum electrolyte concentrations for PWT1D.

Considerations in the Care of Athletes With Type 1 Diabetes Mellitus

Type 1 diabetes mellitus is an autoimmune disease caused by affected individuals’ autoimmune response to their own pancreatic beta-cell. It affects millions of people worldwide. Exercise has numerous health and social benefits for patients with type 1 diabetes mellitus; however, careful management of blood glucose is crucial to minimize the risk of hypoglycemia and hyperglycemia. Anaerobic and aerobic exercises cause different glycemic responses during and after exercise, each of which will affect athletes’ ability to reach their target blood glucose ranges. The optimization of the patient’s macronutrient consumption, especially carbohydrates, the dosage of basal and short-acting insulin, and the frequent monitoring of blood glucose, will enable athletes to perform at peak levels while reducing their risk of dysglycemia. Despite best efforts, hypoglycemia can occur. Recognition of symptoms and rapid treatment with either fast-acting carbohydrates or glucagon is important. Continuous glucose monitoring devices have become more widely used in preventing hypoglycemia.

Behaviour of salivary testosterone and cortisol in men during an Ironman Triathlon

Endurance exercise induces notable acute hormonal responses on the gonadal and adrenal hormones. The purpose of this study was to assess the changes in salivary testosterone (Ts), salivary cortisol (Cs) and T/C ratio during long-distance triathlon. Ten well-trained male triathletes participated in the study and were assessed for hormonal changes at four time-points (pre-competition, post-swimming, post-cycling, and post-running phases). Ts decreased from pre-competition to post-swimming (from 93.37 pg/mL to 57.63 pg/mL; p < .01) and increased during two other parts of the competition to almost pre-competition values (cycling: 79.20 pg/mL, p = .02; running: 89,66 pg/mL, p = .04, respectively). Cs showed a similar behaviour; decreasing in the post-swimming phase (1.74 pg/mL) and increasing in the other transitions (post-cycling: 7.30 pg/mL; post-running: 13.31 pg/mL), with significant differences between pre-competition and post- competition values (p = .01). Conversely, T/C increased significantly from pre-competition to post-swimming phase (p = .04) to later decrease until the end of the competition. Overall, T/C significantly decreased (p < .05). In conclusion, during an Ironman triathlon, hormone values fluctuate in response to the demands of the competition. Ts and Cs decrease after-swimming, increase after-cycling and reach the maximum values after-running. T/C reflects overall catabolic status.

Physical Fitness and the Level of Technical and Tactical Training of Kickboxers

Background: Kickboxing is a dynamically progressing combat sport based on various techniques of punches and kicks. The high level of physical fitness underlies the optimal development of technique in the competitors. The objective of this study was the assessment of the level of fitness of kickboxers and the relationships between fitness and technical and tactical training. Methods: The study included 20 kickboxers aged 18–32 demonstrating the highest level of sporting performance. Their body mass ranged from 75 to 92 kg and their height from 175 to 187 cm. The selection of the group was intentional, and the criteria included training experience and the sports level assessed by the observation of the authors and opinion of the coach. The level of fitness was evaluated with the use of selected trials of International Committee on the Standardization of Physical Fitness Tests and Eurofit tests. Aerobic capacity was tested and indicators of efficiency, activeness and effectiveness of attacks were calculated. Results: A significant correlation between the indicators of technical and tactical training and results of fitness tests was shown. Conclusions: There exists a correlation between efficiency, activeness and effectiveness of attacks and the speed of upper limbs, explosive strength, static strength of a hand, agility, VO₂max and abdominal muscle strength.

Improved glycaemic variability and basal insulin dose reduction during a running competition in recreationally active adults with type 1 diabetes-A single-centre, prospective, controlled observational study

INTRODUCTION

To investigate the glycaemic response, macronutrient intake and insulin management in people with type 1 diabetes (T1D) compared to healthy individuals around a running competition.

MATERIAL AND METHODS

This was a single-centre, prospective, controlled observational study performed in individuals with T1D and healthy people. 24 people (12 T1D) were included in this study (age: T1D 41±12 vs. healthy 38±6 years, females: 3 vs. 6, BMI: 25.53.0 vs. 22.9±2.8 kg/m2). Both groups received an intermittently scanned continuous glucose monitoring (isCGM; FreeStyle Libre 1, Abbott, USA) system to assess glycaemia 24 hours before, during and 24 hours after a running competition. During this period, participants recorded their food intake and insulin administration. Data were analysed via ANOVA and mixed model analyses with post-hoc testing (p≤0.05).

RESULTS

For overall glycaemic ranges in comparison of groups, significant differences were found for time in range (T1D 63±21% vs. healthy 89±13%, p = 0.001), time above range (TAR) 1 (T1D 21±15% vs. healthy 0±0%, p<0.001) and TAR 2 (T1D 8 [0-16%] vs. healthy 0±0%, p<0.001). When glycaemic variability was assessed, people with T1D had a higher glycaemic variability compared to healthy individuals (p<0.0001). Basal insulin dose was significantly reduced when compared against the regular pre-study basal insulin dose (pre-study 22±6 vs. pre-competition day 11±9 (-50±41%), p = 0.02; competition day 15±5 (-32± 1%)).

CONCLUSION

People with T1D have impaired glucose responses around a running competition compared to healthy individuals. However, basal insulin dose reductions were sufficient to prevent further dysglycaemia.

CLINICAL TRIAL ID

drks.de; DRKS00019886.

Glycemic responses to strenuous training in male professional cyclists with type 1 diabetes: a prospective observational study

INTRODUCTION

This prospective observational study sought to establish the glycemic, physiological and dietary demands of strenuous exercise training as part of a 9-day performance camp in a professional cycling team with type 1 diabetes (T1D).

RESEARCH DESIGN AND METHODS

Sixteen male professional cyclists with T1D on multiple daily injections (age: 27±4 years; duration of T1D: 11±5 years; body mass index: 22±2 kg/m²; glycated hemoglobin: 7%±1% (50±6 mmol/mol); maximum rate of oxygen consumption: 73±4 mL/kg/min) performed road cycle sessions (50%-90% of the anaerobic threshold, duration 1-6 hours) over 9 consecutive days. Glycemic (Dexcom G6), nutrition and physiological data were collected throughout. Glycemic data were stratified into predefined glycemic ranges and mapped alongside exercise physiology and nutritional parameters, as well as split into daytime and night-time phases for comparative analysis. Data were assessed by means of analysis of variance and paired t-tests. A p value of ≤0.05 (two-tailed) was statistically significant.

RESULTS

Higher levels of antecedent hypoglycemia in the nocturnal hours were associated with greater time spent in next-day hypoglycemia overall (p=0.003) and during exercise (p=0.019). Occurrence of nocturnal hypoglycemia was associated with over three times the risk of next-day hypoglycemia (p<0.001) and a twofold risk of low glucose during cycling (p<0.001). Moreover, there was trend for a greater amount of time spent in mild hypoglycemia during the night compared with daytime hours (p=0.080).

CONCLUSION

The higher prevalence of nocturnal hypoglycemia was associated with an increased risk of next-day hypoglycemia, which extended to cycle training sessions. These data highlight the potential need for additional prebed carbohydrates and/or insulin dose reduction strategies around exercise training in professional cyclists with T1D.

TRIAL REGISTRATION NUMBER

DRKS00019923.

[Ultramarathon with Type 1 Diabetes]

Ultramarathon with Type 1 Diabetes Abstract. We report the case of a 63-year-old runner with type 1 diabetes mellitus requiring insulin since the age of 21. At the age of 32, he ran his first marathon, and at the age of 34 the first ultramarathon. So far, he has finished more than 90 marathons and ultramarathons. Thanks to an insulin pump and continuous glucose monitoring, he has so far completed 48 24-h-runs with an average distance of 133 km. The analysis of running volume and HbA1c values showed a significant increase in monthly exercise volume, a significant decrease in HbA1c values over the years, and a significant correlation between monthly running kilometers and HbA1c values.

US Army Soldiers With Type 1 Diabetes Mellitus

US Army soldiers diagnosed with type 1 diabetes were previously considered unfit for duty. For highly motivated soldiers, current advanced technologies allow the possibility of not only retention on active duty, but military deployment. We present our experience at Fort Bragg, North Carolina, taking care of soldiers newly diagnosed with type 1 diabetes mellitus. Through intensive diabetes education, extensive military and physical training, optimization of diabetes technology, and remote real-time monitoring, soldiers are able to continue to serve their country in the most specialized roles.

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Zusammenfassung. Wir berichten über einen 64-jährigen Marathonläufer mit bisher 990 erfolgreich gefinishten Marathons, der fälschlicherweise mit Diabetes mellitus Typ 2 diagnostiziert und therapiert wurde. Unter peroraler Therapie mit Metformin kam es zu keiner Reduktion der Blutzuckerwerte. Nach korrekter Diagnose und Therapie mit Insulin ist der Läufer wieder voll im Training, um bald seinen 1000. Marathon zu laufen. Für Sportler mit Diabetes mellitus Typ 1 ist es wichtig, den Blutzucker vor, während und nach Belastung zu messen und die Insulindosis individuell während eines Wettkampfs, wie etwa einem Marathon, zu reduzieren.

Why should people with type 1 diabetes exercise regularly?

Plethoric evidence reminds of the protective effects of exercise against a number of health risks, across all ages, in the general population. The benefits of exercise for individuals with type 2 diabetes are indisputable. An in-depth understanding of energy metabolism has reasonably entailed exercise as a cornerstone in the lifestyle of almost all subjects with type 1 diabetes. Nevertheless, individuals with type 1 diabetes often fail in accomplishing exercise guidelines and they are less active than their peer without diabetes. Two major obstacles are feared by people with type 1 diabetes who wish to exercise regularly: management of blood glucose control and hypoglycemia. Nowadays, strategies, including glucose monitoring technology and insulin pump therapy, have significantly contributed to the participation in regular physical activity, and even in competitive sports, for people with type 1 diabetes. Novel modalities of training, like different intensity, interspersed exercise, are as well promising. The beneficial potential of exercise in type 1 diabetes is multi-faceted, and it has to be fully exploited because it goes beyond the insulin-mimetic action, possibly through immunomodulation.

Glycemic Control and Muscle Damage in 3 Athletes With Type 1 Diabetes During a Successful Performance in a Relay Ultramarathon: A Case Report

Ultramarathon races are fairly demanding and impose substantial physiological stress on healthy athletes. These competitions may thus be considerably more challenging for individuals with diabetes. This case study aims to describe glycemic control, muscle damage, inflammation, and renal function in 3 athletes with type 1 diabetes during a successful performance in a relay ultramarathon. The team completed the race in 29 hours and 28 minutes, earning third place. The total distance covered by each athlete was 68.7, 84.5, and 65.1 km. Most blood glucose levels showed that athletes were in a zone where it was safe to exercise (90-250 mg/dL or 5.0-13.9 mmol/L). Creatine kinase, lactate dehydrogenase, and aspartate aminotransferase serum levels increased 1.2- to 50.7-fold prerace to postrace, and were higher than the reference ranges for all the athletes postrace. Blood leukocytes, neutrophils, and serum C-reactive protein (CRP) increased 1.6- to 52-fold prerace to postrace and were higher than the reference ranges for 2 athletes after the race. Serum creatinine increased 1.2-fold prerace to postrace for all the athletes but did not meet the risk criteria for acute kidney injury. In conclusion, our main findings show evidence of satisfactory glycemic control in athletes with type 1 diabetes during a relay ultramarathon. Moreover, elevation of muscle damage and inflammatory biomarkers occurred without affecting renal function and challenging the maintenance of blood glucose among athletes. These findings are novel and provide an initial understanding of the physiological responses in athletes with type 1 diabetes during ultramarathon races.

Telemedicine in US Army soldiers with type 1 diabetes

A retrospective study of a telemedicine clinic for active duty US Army soldiers with type 1 diabetes was conducted. Fifty-one consecutive patients (mean age 33.9 years) were enrolled into the clinic. All soldiers with known or newly diagnosed type 1 diabetes received three weekly office visits for intensive diabetes education. After this, all communication occurred via a messaging system consisting of texting, web-based download, and/or email to a diabetes management team. For urgent matters, 24/7 direct paging or telephone access was provided. Routine adjustments in insulin dosing were accomplished via email. Soldiers were followed for a mean of 17.1 months. Baseline, three-month, and end of study glycated hemoglobin (A1C) values were 9.8, 7.3, and 6.9, respectively. There were no significant differences in end of study A1C levels between patients with known vs. newly diagnosed type 1 diabetes, nor were there any differences between those patients who received insulin via pump therapy vs. multiple daily injections. Telemedicine was safe and effective in lowering A1C levels in US Army soldiers with type 1 diabetes.

Exercise and type 1 diabetes (T1DM)

Physical exercise is firmly incorporated in the management of type 1 diabetes (T1DM), due to multiple recognized beneficial health effects (cardiovascular disease prevention being preeminent). When glycemic values are not excessively low or high at the time of exercise, few absolute contraindications exist; practical guidelines regarding amount, type, and duration of age-appropriate exercise are regularly updated by entities such as the American Diabetes Association and the International Society for Pediatric and Adolescent Diabetes. Practical implementation of exercise regimens, however, may at times be problematic. In the poorly controlled patient, specific structural changes may occur within skeletal muscle fiber, which is considered by some to be a disease-specific myopathy. Further, even in well-controlled patients, several homeostatic mechanisms regulating carbohydrate metabolism often become impaired, causing hypo- or hyperglycemia during and/or after exercise. Some altered responses may be related to inappropriate exogenous insulin administration, but are often also partly caused by the "metabolic memory" of prior glycemic events. In this context, prior hyperglycemia correlates with increased inflammatory and oxidative stress responses, possibly modulating key exercise-associated cardio-protective pathways. Similarly, prior hypoglycemia correlates with impaired glucose counterregulation, resulting in greater likelihood of further hypoglycemia to develop. Additional exercise responses that may be altered in T1DM include growth factor release, which may be especially important in children and adolescents. These multiple alterations in the exercise response should not discourage physical activity in patients with T1DM, but rather should stimulate the quest for the identification of the exercise formats that maximize beneficial health effects.

Salivary concentrations of cortisol and testosterone and prediction of performance in a professional triathlon competition

The aim of this study was to examine salivary cortisol and testosterone concentrations in professional male athletes during a short triathlon competition using non-invasive methods, and to determine whether these hormone concentrations could be accurate predictors of performance. Eight adult male athletes (age, mean ± SEM: 27.8 ± 3.2 years; body mass index: 21.66 ± 0.42) in a professional triathlon team volunteered to participate in this study. Saliva samples were taken on the competition day and 7 days after competition on a rest day. The performance of the athletes was assessed by their rank order in the competition. Salivary cortisol concentrations were greater on the competition day than on the rest day in the early morning, immediately after waking up, 30 min later, immediately before the start of the competition, and later in the evening. Testosterone concentrations were greater on the competition day in the morning and in the evening. The diurnal rhythm of both cortisol and testosterone concentrations was maintained on both days and the testosterone/cortisol ratio (T/C ratio) was similar between days. The performance of the athletes was positively correlated with salivary cortisol concentration in the early morning of the competition day, but was not correlated with testosterone concentrations at any of the time points. In conclusion, early morning salivary cortisol concentration, but not T/C ratio, could be used to predict performance in athletes during a professional triathlon competition.