Matthew Durand
Medical College of Wisconsin, WI·Physiology
Recovering movement after a stroke depends on exercising hard, yet many stroke survivors cannot push their heart rate high enough or keep a weakened leg working long enough to get there. Both projects in this lab test a shared explanation: after a stroke, the nervous system and blood vessels fail to properly match blood flow and cardiovascular drive to the demands of working muscle.
- Fields
Physiology
Medicine & Clinical Research
Neuroscience
- Topics
stroke
exercise physiology
muscle metaboreflex
- Grants
- 2 known grants, through May 2030
What they work on
- Establish whether the muscle metaboreflex, which raises cardiovascular drive when metabolites accumulate in working muscle, is impaired in the paretic leg of chronic stroke survivors, and relate it to voluntary muscle activation and metabolite levels.
- Test whether greater metaboreflex activation predicts higher maximum heart rate and peak workload on a graded exercise test and more time at or above 70% of heart rate reserve during high-intensity walking.
- Test in a randomized, double-blinded crossover trial whether ischemic conditioning, brief non-invasive limb blood-flow restriction, acutely improves metaboreflex activation and extends time exercising at high heart rates after stroke.
- Determine whether functional sympatholysis, in which active muscle overrides sympathetic narrowing of its own vessels, is impaired in the paretic leg, and whether the impairment tracks with fatigability, motor unit firing rates and metabolite buildup.
- Compare microvascular responses to locally infused acetylcholine, which triggers nitric oxide-mediated dilation, and norepinephrine, which constricts, in stroke survivors versus matched controls, and relate dilation to paretic muscle fatigability.
- Test whether ischemic conditioning produces immediate and sustainable improvements in functional sympatholysis and whether those gains accompany better muscle fatigue resistance.
More about the research
Participants are chronic stroke survivors, and each study compares the paretic leg (the one weakened by the stroke) with the unaffected leg and with age- and sex-matched people who have not had a stroke. Both also test ischemic conditioning, a simple non-invasive procedure that briefly restricts blood flow to a limb, as a way to improve the response.
Why it matters
Stroke survivors often cannot exercise intensely enough to achieve large motor gains, and their legs tire quickly during everyday tasks like walking. Pinpointing impaired reflexes and blood-flow control as causes would give rehabilitation clinicians concrete targets. Testing ischemic conditioning, which is safe, simple and non-invasive, could establish it as an add-on that helps survivors tolerate high-intensity training.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Pierce Boyne
University of Cincinnati, OH·Medicine & Clinical Research
Determine whether high-intensity interval walking training or moderate-intensity aerobic training safely produces larger, lasting gains in walking capacity in 156 people with chronic stroke, in a 3-site randomized trial.
Maria V. Ivanova
University of California-Berkeley, CA·Medicine & Clinical Research
Test whether high-intensity exercise improves language, cognition, movement and emotional well-being in 110 stroke survivors with aphasia, compared with a matched low-intensity exercise control in a randomized trial.
Jeanie Park
Emory University, GA·Physiology
Test whether eight weeks of mindfulness-based stress reduction produces sustained reductions in muscle sympathetic nerve activity, recorded by microneurography, that are linked to lower daytime blood pressure and restored nighttime blood pressure dipping in patients with chronic kidney disease.
The school
Medical College of Wisconsin: 17 labs on PI Pages, $360M a year on research, 44 research doctorates a year.
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