None listed
Conditions
Brief summary
Significant numbers of people are unable to engage in exercise for cardiovascular benefit due to their physical disability. However heat conditioning may be an alternative for people who face such barriers to exercise, but for whom its cardiovascular effects would be particularly beneficial. Patients with peripheral arterial disease (PAD) are one such group to which this applies. Our aim is to determine whether our prior work on the benefits of heat conditioning can be translated to clinical benefit for people with this common condition. This will be tested in a randomised controlled trial of people with PAD, who will undergo either 3-months of heat-stressful health conditioning, or receive advice to undertake supervised exercise as best able. The primary determinant of benefit will be at least a doubling of pain-free walking capacity (primary outcome), along with improvements in blood flow to the affected leg(s), improved cardiorespiratory capacity, quality of life (QOL) and metabolic health. If benefits are seen in this population, we anticipate transferability to people with other cardiovascular and musculoskeletal conditions, and therefore similar obstacles to traditional exercise.
Interventions
Heat conditioning:
Location: School of Physical Education, Sport and Exercise Sciences aquatic facility (University of Otago, Dunedin, NZ). Heat sessions will be supervised by the PI and/or a research fellow, both first aid trained. Attendance will be recorded at each session by the supervising researcher.
Exposure: Participants will be seated in a spa bath at ~38 degrees C for progressive duration (see below). Following the spa bath, heat stress will be maintained for 15-30 min using long-slee
Heat conditioning: Location: School of Physical Education, Sport and Exercise Sciences aquatic facility (University of Otago, Dunedin, NZ). Heat sessions will be supervised by the PI and/or a research fellow, both first aid trained. Attendance will be recorded at each session by the supervising researcher. Exposure: Participants will be seated in a spa bath at ~38 degrees C for progressive duration (see below). Following the spa bath, heat stress will be maintained for 15-30 min using long-sleeved/legged clothing with gentle callisthenic exercise (3 days/week) or seated rest in clothing for other 2 days/week. Callisthenics will be performed in temperate environment (~21 degrees C) using an elastic resistance band incorporating a range of exercises utilising all muscle groups. Contractions will be performed for 1 min followed by 1 min rest (seated or standing). Callisthenics will be performed at an average rate of perceived exertion of 16/20 (Borg scale). Exposure time will progress as follows, if tolerable to increase: Week 1: 15 min spa + 30 min callisthenics 3 days/week (3 exposures) Week 2: 20 min spa + 30 min callisthenics 3 days/week and 20 min spa + 30 min warm rest 1 day/week (4 exposures) Week 3-6: 25 min spa + 30 min callisthenics 3 days/week and 25 min spa + 30 min warm rest 2 days/week (5 exposures) Dosage: After six weeks, if the primary outcome is achieved (>=100% increase in 6 min walking distance), participants will be randomised to either continue this dosage or reduce frequency to 3 days/week. If the primary outcome is not achieved at 6 weeks, the dosage will continue at 5 days/week as described for weeks 3-6 above. Duration: 3 months
Sponsors
Associate Prof. Jim Cotter
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Blinded (masking used) (Investigator)
Eligibility
Sex/Gender
All
Age
45 Years to No maximum
Healthy volunteers
No
Inclusion criteria
1) PAD confirmed by ankle-brachial index in at least one leg of <=0.8 at rest and/or a reduction following exercise; 2) Mild to moderate claudication described, corresponding to Fontaine stage IIa to IIb; 3) > 45 years old; 4) Females must be post-menopausal and not taking hormone replacement therapy; 5) Able to comply with study requirements including repeat visits to the laboratory.
Exclusion criteria
1) Functioning bypass graft in-situ; 2) Isolated disease in aorta / iliac vessels; 3) Type 1 diabetes; 4) Previous occurence of heat intolerance; 5) Unstable angina or myocardial infarction in the past 12 months; 6) Evidence of clinically significant ischaemic heart disease present in the cardiac stress test, and deemed so by the cardiologist.
Outcome results
None listed