Sports and Activity Program Participation by a 14-Year-Old Athlete With New Onset Type 1 Diabetes
BACKGROUND
Physical activity (PA) and exercise reduce the risk of cardiovascular disease, cancer, obesity, and depression and contribute to improved lipid metabolism, sleep quality, and overall health (1–4). For individuals with diabetes, engaging in regular PA and exercise increases insulin sensitivity in skeletal muscle and can improve glycemic control (5–7). Current guidelines recommend at least 60 minutes of moderate to vigorous PA daily for children and adolescents (8,9), yet those with type 1 diabetes (T1D) are less likely to meet these recommendations—with evidence suggesting higher sedentary rates, lower cardiorespiratory fitness (VO2max) and reduced muscle mass when compared with their peers without T1D (10,11). These differences in activity patterns and fitness outcomes are frequently attributed to the fear of exercise-induced hypoglycemia and the challenges associated with maintaining stable blood glucose (BG) levels during and after activity (5,12–18).
Managing BG levels during exercise is a significant challenge for individuals with T1D, particularly for young athletes engaged in various sports. Difficulties maintaining BG stability may deter participation in physical activities and ultimately impact fitness and overall health (19). Aerobic activities, such as running, swimming, or cycling, can lead to rapid drops in BG levels, resulting in symptoms such as dizziness and weakness. On the other hand, anaerobic, or high-intensity, activities (e.g., weightlifting or sprinting), that involve short and intense bursts of strength, can trigger counterregulatory responses that elevate BG levels in the body and potentially lead to hyperglycemia (10,20). These fluctuations present unique challenges for young athletes, as repeated BG excursions could negatively impact athletic performance, increase the risk of injury, and contribute to long-term complications if not carefully managed through carbohydrate intake and insulin adjustments (20). Effective dietary modifications and insulin dosing strategies as well as continuous glucose monitoring are crucial to mitigate the risk of exercise-related hypoglycemia during and after PA (19,21,22).
Youth with T1D face unique physiological and psychosocial challenges, particularly those involved in competitive sports, who require specialized education and support to manage their condition safely and effectively (22). While the link between PA and BG management is well established, few structured, evidence-based programs exist for newly diagnosed adolescent athletes. Authors of existing studies, such as Bishop et al. (23), have focused on general health and weight loss, while others (24) have examined group PA interventions but reported limited impact on glycemic control, pointing to the need for more targeted strategies. To fill this gap, the Wendy Novak Diabetes Institute (WNDI) developed the Clinical Sports and Activity Program (CSAP)—a multidisciplinary initiative offering tailored fitness and nutrition assessments along with individualized diabetes education for athletes.
The CSAP is located at the Christensen Family Sports and Activity Lab in the WNDI at Norton Children’s affiliated with the University of Louisville School of Medicine in Louisville, Kentucky. Participation in the CSAP is offered to all patients with diabetes who participate in sports or PA and are seen for diabetes care at WNDI. Those who participate in the clinical program are offered the opportunity to enroll in an observational study approved by the University of Louisville Institutional Review Board.
The CSAP consists of 2 appointments: a fitness assessment and an educational session. The fitness assessment is performed by a certified clinical exercise physiologist and includes measurements of body composition, flexibility, grip strength, resting metabolic rate (RMR), motor proficiency, and cardiopulmonary fitness (VO2max). BG levels are monitored throughout each appointment. Capillary BG measurements are taken using the Contour® Next Gen BG monitoring system (Ascensia Diabetes Care, Parsippany, New Jersey). If hypoglycemia (BG < 70 mg·dL−1) is identified, exercise is ceased, and treatment is provided. Once BG increases to target range (≥90 mg·dL−1), exercise commences. The patient’s fitness, health, and diabetes management goals are also discussed.
The educational session is facilitated by 2 clinical staff members. The CSAP consists of a registered dietician and a registered nurse who both also held the credentials to be certified diabetes care and education specialists. Individualized education and resources are provided to improve BG control and safety before, during, and after PA and sports. Participants are provided with detailed analysis from insulin intake, BG monitoring, and food logs in relation to diabetes management.
CASE PRESENTATION
A 14-year-old male athlete was diagnosed with T1D after presenting to the emergency department with polyuria, polydipsia, and generalized fatigue. Initial labs were consistent with diabetic ketoacidosis, with a pH of 7.14, bicarbonate of 9, serum osmolality of 308. Hemoglobin A1c (HbA1c) was >15%. He was treated per standard of care with resolution of diabetic ketoacidosis, and diabetes management was initiated with multiple daily insulin injections (MDIs). Following his diagnosis, he expressed concern regarding the management of BG levels during sports and sought assistance from the CSAP to ensure a safe return to his athletic endeavors. He and his family were subsequently referred to the CSAP at the WNDI in Louisville, Kentucky.
The participant completed 3 CSAP visits: baseline (approximately 6 weeks postdiagnosis), 3-month (approximately 4 months postdiagnosis), and 12-month follow-up (approximately 12 months postdiagnosis). Results of clinical assessments and fitness testing are presented in Table 1.
BASELINE VISIT
Prior to the first CSAP appointment, the patient attended 1 clinical follow-up visit for routine diabetes care. He remained on MDIs and had started on a Dexcom G6 continuous glucose monitor (CGM, Dexcom, Inc, San Diego, California). HbA1c was measured at 13%, showing a decrease from the time of diagnosis.
During the fitness assessment appointment, the patient reported participation in soccer practices and games as well as cross country on days when he did not have soccer. BG and blood lactate (BL) measures were taken at the beginning and end of the appointment, with additional measures as needed. A pre-exercise BL value of 1.4 mmol·L−1 and a postexercise value of 5.0 mmol·L−1 were measured. The patient’s time in range (TIR), defined as the percentage of time spent within his target BG range of 70 to 180 mg·dL−1 (25), was calculated to be below the goal range of at least 70%. His glycemic variability from the start to the end of the appointment was 19.3%. Fitness testing was completed without hypoglycemia. The measured flexibility, grip strength, RMR, and motor proficiency were all low-normal. VO2max (44.4 mL·kg−1·min−1; 61st percentile) was below expected. Baseline data are presented in Table 1.
Recommendations for BG management during and after activities were given at the educational session that occurred postfitness assessment. Based on history of BG levels around PA, recommendations for diabetes management and hypoglycemia prevention were provided.
3-MONTH FOLLOW-UP
One additional clinic evaluation was completed by the 3-month follow-up visit. He continued to manage his diabetes with a Dexcom G6 CGM and started using an Omnipod5 hybrid closed loop system (Omnipod, Markham, Ontario, Canada). Due to lab errors, a venous HbA1c was not performed. Using CGM data from the prior 2 weeks, the estimated HbA1c was 7.3%.
During the visit, the participant reported he was still participating in cross country, but soccer had ended. He was waiting for indoor soccer to begin. He completed all fitness testing with a pretest BL of 3.3 mmol·L−1 and posttest BL of 10.9 mmol·L−1. He had a glycemic variability from the start to the end of the appointment of 15.3%. TIR was calculated to be within goal range (70%). Flexibility decreased by 3.0 cm but remained within normal limits. Grip strength, RMR, motor proficiency, and VO2max (58.3 mL·kg−1·min−1; 99th percentile) all improved from baseline. Three-month data are presented in Table 1.
The participant did not return for the educational session after the 3-month follow-up fitness assessment.
12-MONTH FOLLOW-UP
At the 12-month follow-up visit, the patient completed 3 clinical evaluations since the 3-month fitness appointment. Diabetes management was consistent with the 3-month follow-up. An HbA1c of 9.5% was recorded 1 week prior to the fitness assessment appointment.
At the 12-month fitness assessment, the patient was participating in soccer and cross country and about to start competitive swimming. His pretest BL of 1.2 mmol·L−1 and posttest BL of 6.0 mmol·L−1 were measured as well as his glycemic variability from the start to the end of the appointment of 4.4%. The patient’s TIR decreased and was calculated to be below the goal range of at least 70%. Flexibility increased by 1.5 cm from the 3-month follow-up but was still decreased compared with baseline. Grip strength, RMR, and motor proficiency all increased from the last visit. VO2max (58.1 mL·kg−1·min−1; 98th percentile) remained the same. Twelve-month data are presented in Table 1.
Recommendations for preventing lows during swimming, such as turning off basal rates for practices and turning on activity mode for 2 hours postactivity, were made at the educational session following the 12-month fitness assessment. It was noted that nutritional needs had increased since the baseline testing. Nutritional handouts were given, and the recommendation to increase protein intake was made.
DIFFERENCES ACROSS TIMEPOINTS
Between the patient’s baseline and 3-month follow-up, improvements were noted in all categories except flexibility (−3.0 cm; weight [+1.2 kg], BMI [+1.1 kg·m−2], HbA1c [−5.7%], glycemic variability [−4.0%], TIR [+25%], grip strength [+11.0 kg], RMR [+94 kcal·day−1], motor proficiency [+7], and VO2max [+13.9 mL·kg−1·min−1]). The decrease in flexibility could be due to the increase in weight and body fat percentage between visits. According to the National Strength and Conditioning Association, the body’s range of motion can be negatively affected by increased body mass and body fat (16).
Between the 3- and 12-month follow-ups, improvement was found in most areas of fitness, excluding flexibility, even though worsening was found in measures of glycemic control (HbA1c and TIR). Increases in weight (+5.1 kg), BMI (+1.1 kg·m−2), TIR (+8%), grip strength (+19.0 kg), RMR (+485 kcal·day−1), and motor proficiency (+11) as well as decreases in HbA1c (−3.5%) and glycemic variability (−14.9%) between baseline and the 12-month time point demonstrate a positive effect of the CSAP on the participant.
Increases in weight (+2.0 kg), HbA1c (+2.2%), flexibility (+1.5 cm), grip strength (8.0 kg), and motor proficiency (+4) and decreases in VO2max (−0.2 mL·kg−1·min−1), glycemic variability (−10.9%), and TIR (−17%) were all noted between the 3- and 12-month follow-up appointments. At the 12-month follow-up, the participant was struggling to remember to bolus prior to meals due to constant schedule changes. The process of bolusing postprandial can cause an increase in BG levels. This increase over time, even though insulin was given, causes an increase in average BG levels, resulting in an elevated HbA1c (17,18). The participant also failed to return to the nutrition education appointment included with the 3-month follow-up fitness assessment appointment, possibly resulting in minor changes in data values.
DISCUSSION
In this case study, we highlight the potential benefits of a CSAP for individuals newly diagnosed with T1D. The findings from this study demonstrate that participation in the CSAP had a positive impact on the patient’s overall fitness and diabetes management. Significant improvements are seen in HbA1c, glycemic variability, grip strength, and VO2max between the baseline and 3-month follow-up. However, the 12-month follow-up showed increased HbA1c and decreased TIR, likely due to the participant’s inconsistent adherence to insulin bolusing during periods of schedule change. The observed decrease in flexibility may be related to weight gain and increased body (26). However, other fitness parameters, such as grip strength and VO2max, improved consistently over time. These findings suggest that, while structured sports programs can significantly enhance fitness outcomes in athletes with T1D, ongoing education and adherence to diabetes management protocols are critical to sustaining glycemic control.
A new T1D diagnosis is often associated with increased anxiety and depressive symptoms in youth, underscoring the need for comprehensive, multidisciplinary, child-centered interventions to support children and adolescents as they navigate the changes associated with T1D (27). Through the fitness assessments and educational sessions, the participant demonstrated an improved knowledge of diabetes, self-management skills, and understanding of how PA affects T1D. By providing the participant and family with information on treatment of hypoglycemic events, nutritional needs before, during, and after activity, and how various activities and sports affect BG levels, they were given tools to keep the athlete safe while also improving his overall performance.
It is important to note that these recommendations vary depending on treatment modality use. The athlete in this case report was initially managed with MDI, including basal and bolus insulin, and during the study period transitioned to using a CGM and insulin pump with a hybrid closed-loop system. Use of a CGM to monitor BG during exercise is recommended, as it may be difficult to detect symptoms of hypoglycemia or hyperglycemia (28). While recommendations for how to use CGM before, during, and after exercise have been developed (29), having support from a clinical team to guide how these apply to everyone is essential. In addition, use of CGM as part of a hybrid closed-loop system expands the opportunities for management, with use of specific exercise or activity settings. While the best approach to using these settings during exercise is not yet established (28), the CSAP provided individualized recommendations for using these settings to manage diabetes before, during, and after exercise.
The case study outcomes may have been influenced by the patient’s evolving nutrition plan, which was based on Nutrition Care Manual (30) guidelines and tailored to individual goals. Dietary intake was monitored through food journals and recall, with macronutrient needs estimated using RMR and adjusted for activity levels: 45%–50% carbohydrates, <35% fat (<10% saturated), and 15%–20% protein (28). Nutritional recommendations changed over time due to improved fitness and diabetes management, considering activity type, duration, and glycemic responses—especially the risk of hypoglycemia during intense aerobic exercise in those with T1D (10). The CSAP supported ongoing assessment through changes in activity, growth, and fitness.
In this case study, we followed a 14-year-old male athlete with new onset T1D who participated in a CSAP designed for youth with T1D. The potential benefits of this program include providing support to athletes with T1D to navigate the impact exercise has on nutrition, insulin requirements, and risk of hyperglycemia and hypoglycemia.
Future researchers should investigate the long-term effects of CSAPs in a larger sample of youth with T1D. In addition, authors of future studies should use pretest and posttest measures to assess modifiable factors such as self-efficacy, disease knowledge, and perceived barriers to sports participation and diabetes management in youth with T1D as well as compare data across different timepoints and determine the extent to which fitness levels and glycemic parameters change over time. Further investigation into the impact of this type of program on coping with a new diagnosis, continued sports participation, and glycemic control during participation is needed to help inform how best to support young athletes with T1D.
Contributor Notes
Conflicts of Interest and Source of Funding: None.