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How High-Intensity Workouts Affect Adolescents with T1D 

Feb 18, 2020
Editor: Steve Freed, R.PH., CDE

Author: Sandra Zaki, PharmD Candidate, Florida A&M University

High-intensity workouts can result in grave medical conditions for adolescents with type 1 diabetes. 

It has been shown in previous studies that cardiovascular diseases are at the top of the causes of death for people who have type 1 diabetes. This is attributed to arteriosclerosis that kicks off at a young age. Medical experts use arterial compliance to predict the likelihood of cardiovascular disease and its mortality rate. In adolescents with type 1 diabetes (T1D), arterial compliance is generally low. Research has shown that T1D can affect the heart rate through the autonomic nervous system, and as a result, most adolescents with T1D will, most likely, have cardiac autonomic neuropathy. This research was designed to study how and whether high intensity workouts can affect heart rate variability (HRV) in adolescents.  


The study was composed of a total of 43 participants, all of whom were adolescents. Fifteen of them (9 male and six female) had T1D while the other 28 (14 male and 14 female) did not (control). The study group’s age range was 15-21 years with normal weight range. The selection process excluded participants with glycated hemoglobin A1c (HbA1c) ≥ 10.1%, metabolic, cardiovascular, endocrine, medical conditions, tobacco usage, or who were taking medications that could modify their metabolic or cardiovascular activity. Height and BMI measurements were made, and body composition measurements were taken. A graded exercise test was issued to measure their aerobic fitness, which was chosen as a VO2 peak, the peak rate of oxygen consumption. Arterial compliance was measured using a SphygmoCor XCEL as the carotid-femoral pulse wave (PMW). The heart rate was also measured using a chest wrap monitor that transmitted reading to a wristwatch recorder to determine the autonomic regulation of heart rate. The readings were taken over 10 to 12 minutes during each measurement session. The HRV calculation was done using a Kubios HRV software. 

The data collected was analyzed statistically. A comparison between the different groups was made using ttests or Mann Whitney tests. Time series variables were analyzed using the general linear model. Covariates factored in or adjusted for were age, sex, body size and composition, HbA1c, duration of diabetes, and fasting glucose. A P value of <0.05 was considered statistically significant. The sample group (T1D group) had about 6.9 ± 4.6 years since their diabetes diagnosis. The two groups, sample, and the control group showed similar proportion of females or males, height, age, total fat mass, total body fat, lean body mass, VO2 peak, peak workload, and peak heart rate in the study. 

HR, HRV, and EE all came back the same between the sexes. Males had 9% higher PWV (P<0.035) at baseline compared to females. The difference was reduced to 7% after an exercise session. The relationship between EE and glucose was statistically insignificant (P=0.16). Males were 9% taller and had 18% more body mass. The arterial compliance and blood pressure were not different between the groups. Blood pressure was minimally affected by T1D or exercise in both groups. At baseline, most of the cardiovascular measures had no difference between groups due to the similarities in physical activity, body mass, and age between groups.  

The study was insightful though it was limited in that it did not measure the glucose levels in plasma throughout the trial. The study found that adolescents with healthy weight and T1D had a lower heart rate variability when at rest. This is marked as a risk factor for cardiac autonomic neuropathy later in life. They, however, responded to exercise similarly to adolescents who did not have T1D. Adolescents with T1D had higher energy expenditure (EE), even with normal response to exercise. 

Practice Pearls: 

  • Type 1 diabetes is a risk factor for cardiac autonomic neuropathy in adolescents due to increased HRV when at rest. 
  • Physical exercise for type 1 diabetes patients does not equate to good health; it results in higher energy expenditure than people with no diabetes. 
  • Adolescents with T1D will display metabolic and heartrelated irregularities when subjected to highintensity workouts. 


Reference for “How High-Intensity Workouts Affect Adolescents with T1D “:
Ansell S. K. D, Jester M,
Tryggestad J. B, Short K. R. (2020). A pilot study of the effects of a high-intensity aerobic exercise session on heart rate variability and arterial compliance in adolescents with or without type 1 diabetes. Pediatr Diabetes. 2020;1–10. https://doi.org/10.1111/pedi.12983 


Sandra Zaki, PharmD Candidate, Florida A&M University 



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