Engaging in a fitness program is important for everyone. And we all know how hard it can be to find the motivation to start one. However, for people who have suffered a stroke, the hurdles of getting started can be even greater. Stroke survivors have almost half the cardiorespiratory fitness (CRF) and require 40% to 50% more energy to walk compared to individuals who didn’t suffer a stroke. The physical limitations that stroke patients have to deal with can cause an inactive lifestyle that further weakens the body. In turn, the risk of future cardiovascular events increases.
Studies have shown that cardiovascular exercise improves thinking and muscle function. Even though we might feel like we’ve heard about everything there is to know about the world of cardio exercise, there is something new. This new way of approaching stroke rehabilitation is high-intensity interval training (HIIT). HIIT has emerged as a powerful alternative to moderate intensity continuous cardiovascular exercise (MICE) for individuals without other disabilities. HIIT consists of high-intensity bursts of cardiovascular activity followed by bouts of rest. It aims to maximize exercise intensity, decrease the time spent on a session, and increase the total amount of exercise performed.
Approaches to HIIT
Researchers from Canada reviewed the recent literature on the effects of HIIT in stroke rehabilitation. Three types of HIIT were evaluated:
- Short-interval HIIT consists of short, supramaximal high-intensity bursts. A person exerts 100%-120% of their maximum effort. The intervals last about 15-60 seconds with recovery lasting the same amount of time.
- Low-volume HIIT uses short, high-intensity bursts of 10 to 60 seconds at near maximal workload. Active rest periods of walking follow and are 2-4 times longer than the work period. Active recovery reduces any potential symptoms of dizziness.
- Long-interval HIIT is also designed to spend time on longer high-intensity bursts (3-4 minutes) at lower workloads that are 80%-90% of full effort. Active recovery lasts about the same amount of time as the work time.
HIIT sessions last about 20 to 30 minutes. Most stroke-related HIIT studies focused on the use of treadmill walking, either with or without body weight support. One study used a recumbent (sitting) stepper.
Is HIIT effective for stroke recovery?
The evidence suggests that HIIT after stroke is safe. No one reported serious adverse events. Preliminary results from randomized trials suggest that all three types of HIIT are effective in improving mobility and gait outcomes. HIIT improves cardiovascular health and shows early evidence of positively influencing brain recovery. HIIT promoted faster walking speeds and improved cadence and stride length. The brain improvement by HIIT occurred in the first few months after a stroke, but not immediately after a stroke. This mechanism is related to the improved ability to repair damaged areas of the brain. HIIT improves cardiovascular health by decreasing muscle fatigue, increasing the heart’s pumping ability, and improving artery function.
A unique feature of HIIT is its potential to improve exercise enjoyment, raise the ‘happy hormones’ in the brain. As a result, people want to keep exercising. The ‘happy hormones’ or endorphins released after all types of exercise relieve depressive symptoms from a variety of causes including stroke. So, it’s time for your legs to get moving to make your heart and brain healthy. Ask your therapist or doctor if HIIT is the right thing for you!
The lead author of this study is Jennifer Crozier, McMaster University, Hamilton, Ontario, Canada.