Wellness Check: Exercise

2 Minute Medicine is pleased to announce that we are launching Wellness Check, a new series dedicated to exploring new research evidence focused on wellness. Each week, we will report on articles examining different aspects of wellness, including (but not limited to) nutrition, sleep, reproductive health, substance use and mental health. This week, we explore the latest evidence-based updates in exercise.

Exercise may enhance executive function among youth with autism spectrum disorder

1. Chronic exercise interventions had a small to moderate positive effect on executive function overall in children and adolescents with autism spectrum disorder; particularly in cognitive flexibility and inhibitory control.

2. Chronic exercise intervention was shown to have a non-significant effect on working memory.

Evidence Rating Level: 1 (Excellent)

Youth with autism spectrum disorder (ASD) are known to have difficulties in social communication and restricted interests. However, many studies have also indicated that they are at risk of developing executive dysfunction which is a fundamental cognitive skill required for improved overall health. Current literature suggests that exercise can play a positive role in positively affecting cognitive function. In response to a current gap in knowledge, this systematic review and meta-analysis sought to examine the effect of exercise interventions on executive function in children and adolescents with ASD.

From 259 screened records, 14 articles underwent systematic review and 7 were selected for meta-analysis from 2011-2021. Included studies had to investigate the effect of any type of exercise on executive function on children aged 5-17 with a diagnosis of ASD. In addition, studies had to measure cognitive outcomes with validated instruments.

In total, there were 310 children and adolescents with ASD aged 6-18. The Physiotherapy Evidence Database (PEDro) scale was used to assess the quality of each included study. The results of this study demonstrated that exercise intervention had a positive, small-to-moderate effect on overall executive function. With respect to domain-specific executive function, chronic exercise interventions had a small-to-moderate positive effect on cognitive flexibility and inhibitory control. In contrast, this study found a non-significant effect of exercise on working memory amongst this population. However, this study was limited by the heterogeneity in measurement of executive function which made the synthesis of results more difficult. Nonetheless, this study provided early evidence for future studies to investigate the influence of variables such as age and intensity of physical activity.

Aerobic and combined exercise may improve cancer related fatigue

1. Aerobic exercise alone or combined with resistance training improves cancer related fatigue better than other forms of activity.

2. Studies reporting the best improvements followed low to moderate intensity regimens.

Evidence Rating Level: 1 (Excellent) 

Cancer related fatigue (CRF) is the most common disease in cancer patients who receive cancer treatment affecting 70-100% of patients. This condition is very debilitating and can be more distressing to daily function than the pain associated with the cancer itself. As exercise is often recommended to improve CRF, the objective of the current systematic review was to evaluate the effects of aerobic, resistance, endurance and combined exercise modalities on CRF.

From 827 identified records, 15 randomized controlled trials were included in the present study from January 1^st 2001 to September 1^st 2019. A total of 1664 patients (23% men) were included. To be eligible, studies had to include adult patients living with a cancer diagnosis undergoing treatment. Studies had to evaluate various modalities of exercise and evaluate its influence on fatigue, as measured by a self-report questionnaire, to be included. Complex forms of exercise which required complex motor patterns (e.g. tai chi, pilates, etc) were excluded.

Results demonstrated that aerobic exercise improved CRF better than other forms of activity. However, good outcomes were also achieved when combined with resistance training. Low to moderate intensities worked equally well for both men and women and optimal results were found to occur when performed at least 2 days/week for 8 or more weeks. However, this study was limited in the inclusion of a small number of studies and lack of variety of cancer types, as there was a predominance of breast and prostate cancers. Despite this, the present study offered support for the inclusion of daily activities in life of a cancer patient suffering from CRF.

Structured aerobic exercise may produce less weight loss than expected

1. In this study, significant weight loss occurred in the group performing aerobic exercise that expended 20 kcal/kg/week but was only half of what was expected if there was no compensation.

2. In the group that expended 8 kcal/kg/week, there was no change in weight and no significant change in any component of energy expenditure.

Evidence Rating Level: 1 (Excellent)

Energy expenditure is known to increase in proportion to the amount of physical activity. However, the contribution to total energy expenditure is likely offset by decreases in other components of daily energy expenditure. Since the extent to which the energy deficit induced by exercise is not well understood, the present study was designed to identify mechanisms responsible for weight compensation. The primary objective of this study was to evaluate changes in components of daily energy expenditure after 24 weeks of exercise training by comparing two doses of aerobic exercise.

This ancillary study of the Examination of Mechanisms of Exercise-induced Weight compensation study included 53 patients (n=13 controls, n=14 at 8 kcal/kg/week of aerobic exercise, n=15 at 20 kca/kg/week of aerobic exercise) with a body mass index between 25 kg/m² and 45 kg/m² who were healthy and not currently exercising >20 minutes 3 times per week. Notable exclusion criteria included prior participation in a weight loss program and prior bariatric surgery. Todal daily energy expenditure (TDEE) was measured in free-living condition by doubly labeled water and in sedentary conditions in a metabolic chamber over 24hrs.

Results demonstrated that the 20 kcal/kg/week group had significant weight loss, although only half of what was expected, likely due to decreased overall 24-hour energy expenditure. In addition, the 8 kcal/kg/week group did not experience any weight loss and had no significant change in overall energy expenditure. This study was limited by the environment of the metabolic chamber which may not apply to free living conditions. However, the results of this study were strengthened due to its success at ensuring individuals adhered to their respective exercise regimen.

Image: PD

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