High-Intensity Interval Training in Stroke Rehabilitation

Abstract

After stroke, people with weakness enter a vicious cycle of limited activity and deconditioning that limits functional recovery and exacerbates cardiovascular risk factors. Conventional aerobic exercise improves aerobic capacity, function, and overall cardiometabolic health after stroke. Recently, a new exercise strategy has shown greater effectiveness than conventional aerobic exercise for improving aerobic capacity and other outcomes among healthy adults and people with heart disease. This strategy, called high-intensity interval training (HIT), uses bursts of concentrated effort alternated with recovery periods to maximize exercise intensity. Three poststroke HIT studies have shown preliminary effectiveness for improving functional recovery. However, these studies were varied in approach and the safety of poststroke HIT has received little attention. The objectives of this narrative review are to (1) propose a framework for categorizing HIT protocols; (2) summarize the safety and effectiveness evidence of HIT among healthy adults and people with heart disease and stroke; (3) discuss theoretical mechanisms, protocol selection, and safety considerations for poststroke HIT; and (4) provide directions for future research.

Factors Influencing the Efficacy of Aerobic Exercise for Improving Fitness and Walking Capacity After Stroke

“…18,19 It is plausible that AEX mode, AEX intensity, AEX volume, stroke chronicity and baseline function would be key factors that influence AEX effect sizes post-stroke. 20,21 For example, neuroplasticity principles indicate that training effectiveness is largely determined by the task-specificity (mode), intensity and repetition (volume) of practice. 21,22 On the other hand, it has been suggested that AEX could improve walking speed and endurance after stroke, regardless of task-specificity (AEX mode).…”

Does Aerobic Exercise and the FITT Principle Fit into Stroke Recovery?

“…High-intensity interval training (HIT) is a method that may facilitate the attainment of higher aerobic intensities after stroke [54]. HIT involves concentrated bursts of intense exercise alternated with recovery periods, in varying combinations of burst/recovery duration and intensity.…”

Preliminary safety analysis of high-intensity interval training (HIIT) in persons with chronic stroke

“…Approximately 50% of persons with stroke exhibit hemiparesis, or weakness on one side of the body (Go et al 2014;Gresham et al 1979). As a consequence, a majority of persons with stroke have increased fall risk, decreased gait velocity, and exhibit markedly diminished aerobic capacity (Billinger et al 2012;Billinger et al 2014;Boyne et al 2013;Michael et al 2005). This diminished capacity is related to long-term risk for additional cardiac events and recurrent stroke (Mora et al 2007;Tang et al 2014).…”

“…However, recent evidence suggests that exercise conducted at higher intensities may be more efficacious than moderate-intensity exercise (Boyne et al 2013;Boyne et al 2015;Burgomaster et al 2005;Hornby et al 2011;Macpherson et al 2011;Rognmo et al 2014). …”

“…Evidence supporting the use of HIIT in specific high-risk clinical populations soon followed (Boyne et al 2013). For example, Wisloff et al (2007) shown to elicit significantly greater improvements in gait recovery (Lau and Mak 2011;Pohl et al 2002).…”