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.
1. Transwomen competing in sports may retain strength advantages over cisgender women even after 3 years of hormone therapy.
2. Transwomen have red blood cell findings equivalent to those of cis gender women after 4 months of hormone therapy, thereby reducing their endurance performance.
Evidence Level Rating: 1 (Excellent)
Presently, there is a lack of prospective studies investigating changes in athletic performance in transgender athletes after undergoing gender affirming hormone treatment (GAHT) which is known to have a feminizing effect on the body. It is also known that World Athletics requires that transgender athletes and athletes with differences of sexual development have testosterone levels ≤5 nmol/L to be eligible for the female category. As a result, the objective of this study was to systematically review the literature to determine the influence of GAHT on athletic performance.
This systematic review included 24 studies from 1999-2020. Eligible studies measured at least one of the variables of interest, included transwomen, and were written in English. The quality of the studies were examined by the Effective Public Health Practise Project (EPHPP) tool and were deemed to be moderate in quality. GAHT treatment varied based on the study, in line with the individualized approach advised by the WPATH Standards of Care. Study outcomes assessed the influence of GAHT on muscular area, lean body mass, muscular strength, and haemoglobin/hematocrit.
After taking the strength parameter data collectively, results indicated that after 12-36 months of GAHT, transwomen still retained a strength advantage over cisgender women. In contrast to these strength findings, transwomen were found to have decreased haemoglobin/hematocrit levels (impacting endurance performance) after 3-4 months of GAHT, matching that of cisgender women. One key strength of the present study included the use of the EHPP tool to account for the overall quality of the studies included. By contrast, this study was limited as only studies from Western countries were included, contributing to geographical bias. Nonetheless, this study was significant in suggesting strength may be retained after GAHT in transwomen in the first 3 years of treatment.
1. Use of accelerometer/pedometer-only and commercial health wearable-only were the most effective at reducing body weight in comparison with the other groups.
2. Multicomponent accelerometer/pedometer and commercial health wearable-only interventions were the most effective at reducing body mass index in comparison to the other groups.
Evidence Rating Level: 1 (Excellent)
Being overweight remains a significant public health challenge, of which physical inactivity is a major contributor. Physical activity wearables have the potential to encourage physical activity; however, there is a lack of evidence pointing to the most effective method. As a result, the goal of this study was to perform a systemic review of randomized controlled trials (RCTs) investigating the effect of health wearable-based physical activity interventions on body mass index (BMI) and bodyweight reduction in overweight/obese individuals with chronic health conditions.
Of 641 screened records, 31 studies (2268 patients) from December 2019 to September 2020 were included in the analysis. Included studies met the following criteria: participants were overweight/obese and/or had at least one chronic comorbidity and studied the effect of health-wearable interventions on weight or BMI. The six comparison groups included four wearable interventions, one comparison group (non-health wearable physical activity) and control group (usual care, waitlist). Network geometry and network meta-analysis were used to compare the effect of each intervention on the primary outcome.
Results stated that the commercial health-wearable only and the accelerometer/pedometer-only groups were most effective at reducing bodyweight compared with the control. With respect to BMI reduction, commercial health wearable-only and multicomponent accelerometer/pedometer interventions were found to be most effective. One of the key strengths of this study was its use of strict criteria which allowed for a homogenous sample. However, due to insufficient direct comparisons available to assess BMI reduction, the results for this outcome must be interpreted with caution. As a whole, these results suggest that the use of health wearable-based physical activity interventions may help achieve modest bodyweight and/or BMI reductions.
1. Quality based physical activity interventions increased student’s cognition, mainly in primary education as well as academic performance (primarily mathematics-related skills).
2. Quantity based physical activity interventions had a very small effect on academic performance.
Evidence Rating Level: 1 (Excellent)
It is well known in the literature that physical activity is positively associated with enhanced cognition and academic performance especially in children and adolescents. Although there is an abundance of studies looking at these associations, there lacks a systematic review and meta-analysis synthesizing the available evidence. As a result, the primary aim of the present meta-analysis was to determine the effect of studies whose objective was to optimize physical education quantity, quality, or both, on cognition and academic performance in children and adolescents.
This systematic review and meta-analysis included 19 randomized controlled trials from electronic databases from inception to January 3rd, 2021. A total of 8676 healthy children and adolescents (53.5% boys) from 11 countries were included. To be eligible, studies had to have assessed the effect of physical education quantity (e.g., increasing the number of physical education sessions per week), or quality (e.g., enriched lessons), or both, on changes in cognition and/or academic performance in youth aged 5-18 years. 6 studies examined quantity based physical education, 13 examined quality-based physical education and 4 combined the two interventions. The Physiotherapy Evidence Database (PEDro) was used to appraise each study critically.
Results demonstrated that quality-based physical education interventions increased both student’s cognition in primary education as well as academic performance, particularly in mathematics related skills. Conversely, quantity-based interventions had a very small effect on academic performance. This study was limited by the inclusion of a small number of trials and the heterogeneity of results. Nonetheless, the results from this study provide early evidence suggesting that improving the quality of physical education classes may be a worthwhile investment in improving cognition and academic performance in youth ages 5-18.
1. The risk of developing atrial fibrillation was significantly greater in athletes compared to non-athletes.
2. Younger (<55 yrs) and mixed sport athletes had a greater risk of developing atrial fibrillation than older athletes and those participating in endurance sports respectively.
Evidence Rating Level: 1 (Excellent)
Many studies have shown that exercise can reduce cardiac arrhythmias such as atrial fibrillation (AF). Interestingly, the relationship with exercise follows a U-shaped curve, meaning that both a lack of physical activity or high-intensity/high-volume exercise may increase the prevalence of AF. The influence of sport type and cardiovascular disease remains to be elucidated in studies examining the burden of AF in athletic populations and as a result, the present systematic review and meta-analysis seeks to address this gap by incorporating such variables.
From 3885 screened records, 13 studies (70,487 participants) from 1990 to December 2020 were included. Studies were eligible if they reported the number of AF/Atrial flutter cases in athletes with non-athlete control groups and were either case-control or cohort studies. Studies that did not include a control group or had participants (18 years or older) that did not perform regular exercise training for at least a 2-year period were excluded. Qualitative risk of bias assessment was done using the CLARITY tool and a meta regression was done to determine the risk of AF in athletes versus non athletes.
There were three analyses performed to determine the effect of athletic involvement, presence of cardiovascular risk factors and the mode of exercise on AF burden. Results demonstrated that athletes were at higher risk of developing AF compared to non-athletes, especially those who participated in mixed sport and who were younger. This study was limited by the broad range of sports that fall under the mixed sport category, thereby complicating the determination of the effect of specific training factors. However, unlike other studies, the present analysis included athletes, physically active individuals, and sedentary individuals, which strengthens the observed relationship. As a whole, these findings helped provide early evidence for the effect of age, sport modality and athleticism on AF burden.
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