Clinical trial NCT03285386: Priming Exercise in Type 1 Diabetes
Official title: The Effects of Prior Exercise on Pulmonary Oxygen Uptake Kinetics and the Power-Duration Relationship in Type 1 Diabetes
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Type 1 Diabetes Mellitus
Lead sponsor: Liverpool Hope University
Sponsor class: OTHER
First posted: 2017-09-18
Enrollment: 7
Sex: MALE
Minimum age (years): 18
Maximum age (years): 40
Standard ages: ADULT
Accepts healthy volunteers: no
Allocation: NON_RANDOMIZED
Intervention model: SINGLE_GROUP
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.
Primary purpose: BASIC_SCIENCE

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.

Eligibility criteria: 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.

Primary outcomes:
measure: Critical power
timeFrame: 3-9 weeks
measure: Phase II time constant of pulmonary oxygen uptake kinetics
timeFrame: 3-9 weeks
measure: Time constant for muscle deoxygenation kinetics (assessed by near-infrared spectroscopy)
timeFrame: 3-9 weeks
Secondary outcomes:
measure: W'
timeFrame: 3-9 weeks
measure: Time constant for heart rate kinetics
timeFrame: 3-9 weeks
Other outcomes:
Locations:
city: Liverpool
country: United Kingdom
facility: Liverpool Hope University
state: Merseyside
Study officials:
affiliation: Liverpool Hope University
name: Richie P Goulding
role: PRINCIPAL_INVESTIGATOR
References:
citation: Goulding RP, Roche DM, Marwood S. Prior exercise speeds pulmonary oxygen uptake kinetics and increases critical power during supine but not upright cycling. Exp Physiol. 2017 Sep 1;102(9):1158-1176. doi: 10.1113/EP086304. Epub 2017 Jul 26.
citation: Behnke BJ, Kindig CA, McDonough P, Poole DC, Sexton WL. Dynamics of microvascular oxygen pressure during rest-contraction transition in skeletal muscle of diabetic rats. Am J Physiol Heart Circ Physiol. 2002 Sep;283(3):H926-32. doi: 10.1152/ajpheart.00059.2002.
citation: Sexton WL, Poole DC, Mathieu-Costello O. Microcirculatory structure-function relationships in skeletal muscle of diabetic rats. Am J Physiol. 1994 Apr;266(4 Pt 2):H1502-11. doi: 10.1152/ajpheart.1994.266.4.H1502.
citation: Kindig CA, Sexton WL, Fedde MR, Poole DC. Skeletal muscle microcirculatory structure and hemodynamics in diabetes. Respir Physiol. 1998 Feb;111(2):163-75. doi: 10.1016/s0034-5687(97)00122-9.
citation: Burnley M, Davison G, Baker JR. Effects of priming exercise on VO2 kinetics and the power-duration relationship. Med Sci Sports Exerc. 2011 Nov;43(11):2171-9. doi: 10.1249/MSS.0b013e31821ff26d.