Type 1 Diabetes Mellitus
Conditions
Brief summary
Critical power is an important threshold in exercise physiology, and is an important determinant of the ability to tolerate high-intensity exercise. The ability to tolerate such exercise is drastically impaired in certain chronic conditions, such as type 1 diabetes. Whilst the most important physiological factors that determine critical power have yet to be determined, previous work from our laboratory suggests that it is related to the speed of oxygen uptake at the onset of exercise. This study will look to utilise priming exercise as an intervention to improve the speed of these oxygen uptake kinetics, and thus critical power and exercise tolerance in individuals with type 1 diabetes. We hypothesize that oxygen uptake kinetics will be faster and critical power will be higher when exercise is performed with compared to without a prior bout of high-intensity priming exercise in a population of individuals with type 1 diabetes.
Detailed description
The ability to tolerate high-intensity exercise, or exercise tolerance, is a key factor that can influence clinical outcomes in a range of conditions. The critical power is an important physiological threshold that demarcates exercise intensities that can be sustained for prolonged periods (i.e. below critical power) from intensities that result in exhaustion in a relatively short period of time (i.e. 2-30 minutes, above critical power). Critical power is therefore a key determinant of exercise tolerance. The speed with which oxygen uptake rises at the onset of exercise (i.e. oxygen uptake kinetics) has been shown by work from our laboratory to be a key determinant of critical power. One intervention that can acutely improve the oxygen uptake kinetics is the performance of a prior bout of high-intensity exercise, known as priming exercise. Patients with type 1 diabetes have previously been shown to have impaired exercise tolerance compared to healthy controls. The performance of priming exercise therefore represents a potential intervention to acutely improve oxygen uptake kinetics, and therefore critical power and exercise tolerance, in type 1 diabetic individuals. The purpose of this study is therefore to assess the influence of priming exercise on oxygen uptake kinetics and critical power in a population of type 1 diabetic individuals.
Interventions
BEHAVIORALPriming exercise
All participants will perform a bout of high-intensity priming exercise for 6 minutes, 10 minutes prior to undertaking an exhaustive exercise test on four separate occasions.
BEHAVIORALControl Exercise
All participants will perform 3 minutes of baseline cycling prior to undertaking an exhaustive exercise test on four separate occasions.
Sponsors
Liverpool Hope University
Study design
Allocation
NON_RANDOMIZED
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Intervention model description
Participants will serve as their own controls. Participants will alternate between primed (experimental condition) and non-primed (control condition) in their visits.
Eligibility
Sex/Gender
MALE
Age
18 Years to 40 Years
Healthy volunteers
No
Inclusion criteria
Suffering from Type 1 diabetes with a diagnosed disease duration of 2 - 20 years and no comorbidities.
Exclusion criteria
History of stroke, congestive heart failure, hypertension, or cardiopulmonary disease. Current smoking or have been smoking within the last 12 months Symptomatic autonomic or distal neuropathy HbA1c \> 64 mmol/mol Hypoglycaemia unawareness in the last 6 months Taking any medications other than insulin.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Critical power | 3-9 weeks | The power asymptote of the hyperbolic relationship between power and the tolerable duration of exercise. |
| Phase II time constant of pulmonary oxygen uptake kinetics | 3-9 weeks | Time taken for oxygen uptake to attain 63% of its asymptotic amplitude. |
| Time constant for muscle deoxygenation kinetics (assessed by near-infrared spectroscopy) | 3-9 weeks | Time taken for muscle deoxyhaemoglobin to attain 63% of its asymptotic amplitude. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| W' | 3-9 weeks | Curvature constant of the power-duration relationship. Finite work capacity available above critical power. |
| Time constant for heart rate kinetics | 3-9 weeks | Time taken for heart rate to attain 63% of its asymptotic amplitude. |
Countries
United Kingdom
Outcome results
None listed