The Sprint to Slow-Down Brain Decline

Contributed by Sara Thompson, MSc, Faculty of Kinesiology and Physical Education, Human Physiology Research Unit, University of Toronto

As we learned from a recent FTG post by Fiona Callender, exercise can improve the cognitive decline that occurs with age. In her article, Ms. Callender highlighted the use of resistance training to improve cognitive function in patients with dementia (Nagamatsu et al., 2012). But what about high-intensity exercise? There has been increasing focus on the physiological benefits of high-intensity exercise, however the psychological benefits of this type of training is less established. In fact, it has been speculated that exercising at high intensities might impair brain function (Tomporowski, 2003)! In two recently conducted studies, researchers refuted this notion and highlighted the benefits of high-intensity exercise on cognition.

In a 2014 study, Alves and colleagues assessed selective attention and short-term memory following interval exercise in 22 middle-aged men and women (mean age = 53.7 yrs). Each participant performed both a high-intensity interval training (HIIT) session and a control session, which was comprised of light stretching. The HIIT session consisted of ten 1-minute sprints on a stationary bike at 80% of their heart rate reserve (HRreserve), alternating with 1-minute at 60% of HRreserve. HRreserve corresponds to a participant’s maximum heart rate minus their resting heart rate, and is a target number commonly used to monitor exercise intensity. Participants were assessed on selective attention and short-term memory before and after each exercise session. After HIIT, the participants significantly improved in the Stroop “colour word” test (Stroop, 1935), a measure of selective attention. The researchers observed that following HIIT, the participants were significantly faster at completing the test than following the control session. The participants did not improve in the short-term memory task following HIIT, but were able to repeat their pre-exercise scores.

In a similar study, Tonoli and colleagues (2015) assessed cognitive function following HIIT in type 1 diabetics (T1D) and healthy control subjects. These researchers aimed to assess cognitive function in T1D, as it’s hypothesized that this population has impaired cognition due to chronic hypo and hyperglycaemia (Auer, 2004; Wrighten et al., 2009). Ten T1D and 10 age-, sex- and fitness level-matched controls (ages: 18-44 years) were assessed on cognitive tests before and after HIIT. The HIIT consisted of 10 bouts of 1-minute cycling intervals at 90% of their maximum load, interspersed with 1-minute at a low workload. The cognitive tests assessed were the Stroop test and a spatial memory task. The control subjects and T1D had similar improvements in cognition following a single bout of high-intensity exercise, suggesting that T1D’s response to exercise is comparable to that of healthy individuals. The authors suggest that a long-term high-intensity fitness program could improve brain health in T1D.

Both of these studies observed improvements in cognition after high-intensity exercise – and only after one session! While not all measures of cognitive function improved, there were no cognitive measures that declined following exercise. These studies used almost identical protocols consisting of 10 bouts of high-intensity cycling, separated with 1 minute of moderate cycling. This suggests that this type of HIIT session is effective in improving cognitive function in both middle-aged adults and a diseased population in which cognition is known to be impaired. The effects of long-term high-intensity exercise on lasting cognitive function is promising and is an important area of research to be studied in the future.

Sources:

Alves, C.R., Tessaro, V.H., Teixeira, L.A., Murakava, K., Roschel, H., Gualano, B., & Takito, M.Y. (2014). Influence of Acute High-Intensity Aerobic Interval Exercise Bout on Selective Attention and Short-Term Memory Tasks. Perceptual & Motor Skills, 118(1), 63-72.

Auer, R.N. 2004. Hypoglycemic brain damage. Metabolic Brain Disease, 19: 169–75.

Nagamatsu, L.S., Handy, T.C., Hsu, C.L., Voss, M., & Liu-Ambrose, T. (2012). Resistance training promostes cognitive and functional brain plasticity in seniors with probable mild cognitive impairment. Archives of Internal Medicine, 172(8), 666-668.

Stroop , J.R. (1935). Studies of interference in serial verbal reactions. Journal of Experimental Psychology, 18, 643-662.

Tomporowski, P.D. (2003). Effects of acute bouts of exercise on cognition. Acta Psychologica, 112(3), 297-324.

Tonoli, C., Heyman, E., Buyse, L., Roelands, B., Piacentini, M.F., Bailey, S., Pattyn, N., Berthoin, S., & Meeusen, R.(2015). Neurotrophins and cognitive functions in T1D compared with healthy controls: effects of a high-intensity exercise. Applied Physiology, Nutrition & Metabolism, 40(1), 20-27.

Wrighten, S.A., Piroli, G.G., Grillo, C.A., & Reagan, L.P. (2009). A look inside the

diabetic brain: contributors to diabetes-induced brain aging. Biochimica et Biophysica Acta, 1792, 444–453.