Type 1 diabetes may, in time, cause lung dysfunction including airflow limitation. We hypothesized that ventilatory flow morphology during a cardiopulmonary exercise test (CPET) would be altered in adult men with well-controlled type 1 diabetes. Thirteen men with type 1 diabetes [glycated hemoglobin A1c 59 (9) mmol/mol or 7.5 (0.8)%, duration of diabetes 12 (9) years, and age 33.9 (6.6) years] without diagnosed diabetes-related complications and 13 healthy male controls [age 37.2 (8.6) years] underwent CPET on a cycle ergometer (40 W increments every 3 min until volitional fatigue). We used a principal component analysis based method to quantify ventilatory flow dynamics throughout the CPET protocol. Last minute of each increment, peak exercise, and recovery were examined using linear mixed models, which accounted for relative peak oxygen uptake and minute ventilation. The type 1 diabetes participants had lower expiratory peak flow (P = 0.008) and attenuated slope from expiration onset to expiratory peak flow (P = 0.012) at peak exercise when compared with the healthy controls. Instead, during submaximal exercise and recovery, the type 1 diabetes participants possessed similar ventilatory flow dynamics to that of the healthy controls. In conclusion, men with relatively well-controlled type 1 diabetes and without clinical evidence of diabetes-related complications exhibited attenuated expiratory flow at peak exercise independently of peak oxygen uptake and minute ventilation. This study demonstrates that acute exercise reveals alterations in ventilatory function in men with type 1 diabetes but not until peak exercise.

A perturbed postural balance test can be used to investigate balance control under mechanical disturbances. The test is typically performed using purpose-built movable force plates. As instrumented treadmills become increasingly common in biomechanics laboratories and in clinical settings, these devices could be potentially used to assess and train balance control. The purpose of the study was to investigate how an instrumented treadmill applies to perturbed postural balance test. This was investigated by assessing the precision and reliability of the treadmill belt movement and the test-retest reliability of perturbed postural balance test over 5 days. Postural balance variables were calculated from the center of pressure trajectory and included peak displacement, time to peak displacement, and recovery displacement. Additionally, the study investigated short-term learning effects over the 5 days. Eight healthy participants (aged 24–43 years) were assessed for 5 consecutive days with four different perturbation protocols. Center of pressure (COP) data were collected using the force plates of the treadmill while participant and belt movements were measured with an optical motion capture system. The results show that the treadmill can reliably deliver the intended perturbations with <1% deviation in total displacement and with minimal variability between days and participants (typical errors 0.06–2.71%). However, the treadmill was not able to reach the programmed 4 m/s2 acceleration, reaching only about 75% of it. Test–retest reliability of the selected postural balance variables ranged from poor to good (ICC 0.156–0.752) with typical errors between 4.3 and 28.2%. Learning effects were detected based on linear or quadratic trends (p < 0.05) in peak displacement of the slow forward and fast backward protocols and in time to peak displacement in slow and fast backward protocols. The participants altered the initial location of the COP relative to the foot depending on the direction of the perturbation. In conclusion, the precision and accuracy of belt movement were found to be excellent. Test-retest reliability of the balance test utilizing an instrumented treadmill ranged from poor to good which is, in line with previous investigations using purpose-built devices for perturbed postural balance assessment.

In type 1 diabetes, it is important to prevent diabetes‐related complications and postural instability may be one clinically observable manifestation early on. This study was set to investigate differences between type 1 diabetics and healthy controls in variables of instrumented posturography assessment to inform about the potential of the assessment in early detection of diabetes‐related complications. Eighteen type 1 diabetics with no apparent complications (HbA1c = 58 ± 9 mmol/L, diabetes duration = 15 ± 7 years) and 35 healthy controls underwent six 1‐min two feet standing postural stability tests on a force plate. Study groups were comparable in age and anthropometric and performed the test with eyes open, eyes closed (EC), and EC head up with and without unstable padding. Type 1 diabetics exhibited greater sway (path length, p = 0.044 and standard deviation of velocity, p = 0.039) during the EC test with the unstable pad. Also, power spectral density indicated greater relative power (p = 0.043) in the high‐frequency band in the test with EC head up on the unstable pad and somatosensory activity increased more (p = 0.038) when the unstable pad was added to the EC test. Type 1 diabetes may induce subtle changes in postural control requiring more active balancing when stability is challenged. Postural assessment using a portable easy‐to‐use force plate shows promise in detecting a diabetes‐related decline in postural control that may be used as a sensitive biomarker of early‐phase diabetes‐related complications.

Background Little is known about the associations of different depths of individualization of the exercise intervention on cardiorespiratory fitness (CRF), metabolic outcomes and cardiac autonomic regulation in at-risk subjects. This randomized trial compared the effect of general physical activity (PA) guideline -targeted and highly individualized exercise intervention on maximal oxygen uptake, heart rate variability, body composition, and glucose and lipid profiles in fertile-aged women with increased risk for gestational diabetes. Methods Forty-five women with previous gestational diabetes or BMI>30kg/m 2 were randomized into general advice without intervention (Group 1), individualized intervention planned according to PA questionnaires and general guidelines for exercise training (Group 2) and highly individualized intervention based on results from the pre-intervention cardiopulmonary exercise test (CPET) groups (Group 3). All subjects performed pre-intervention CPET on a cycle ergometer with step incremental protocol until volitional fatigue, followed by a 3-month intervention period and post-intervention CPET. Examinations included HRV assessment during CPET and body composition (bioimpedance), blood glucose and lipid profiles. Results Total dropout was 53.8% at various points of the study leaving 8 subjects in Group 1, 12 subjects in Group 2 and 10 subjects in Group 3. CRF improved only in Group 3 (+1.9 ml/kg/min, 95% CI 0.3 to 3.5). This was associated with an increase in high-density lipoprotein (0.18 mmol/L, 95% CI 0.04 to 0.32) and increased HRV. In Group 2, we found a decrease in body mass index (-0.7 kg/m 2, 95% CI -1.3 to -0.1), fasting insulin (-4.14 mU/L, 95% CI -6.58 to -1.70), insulin resistance (-1.21, 95% CI -1.88 to -0.54), and low-density lipoprotein (-0.44 mmol/L, 95% CI -0.79 to -0.09). The dropouts in Group 1 had significantly less weight, smaller waist circumference, less visceral fat, and higher maximal oxygen uptake compared to the continuers in Group 1. Conclusions To improve CRF and cardiac autonomic function the exercise intervention should be highly individualized. PA intervention focused to achieve general exercise guidelines is not enough to improve CRF over 3-month period but combined with weight loss has beneficial effects on the metabolic profile. In randomized controlled trials, dropout may be biased. Trial Registration clinicaltrials.gov (NCT01675271)