Physical Activity Intolerance and Cardiorespiratory Dysfunction in Patients with Moderate-to-Severe Traumatic Brain Injury Abstract Moderate-to-severe traumatic brain injury (TBI) is a chronic health condition with multi-systemic effects. Survivors face significant long-term functional limitations, including physical activity intolerance and disordered sleep. Persistent cardiorespiratory dysfunction is a potentially modifiable yet often overlooked major contributor to the alarmingly high long-term morbidity and mortality rates in these patients. This narrative review was developed through systematic and non-systematic searches for research relating cardiorespiratory function to moderate-to-severe TBI. The literature reveals patients who have survived moderate-to-severe TBI have ~ 25–35% reduction in maximal aerobic capacity 6–18 months post-injury, resting pulmonary capacity parameters that are reduced 25–40% for weeks to years post-injury, increased sedentary behavior, and elevated risk of cardiorespiratory-related morbidity and mortality. Synthesis of data from other patient populations reveals that cardiorespiratory dysfunction is likely a consequence of ventilator-induced diaphragmatic dysfunction (VIDD), which is not currently addressed in TBI management. Thus, cardiopulmonary exercise testing should be routinely performed in this patient population and those with cardiorespiratory deficits should be further evaluated for diaphragmatic dysfunction. Lack of targeted treatment for underlying cardiorespiratory dysfunction, including VIDD, likely contributes to physical activity intolerance and poor functional outcomes in these patients. Interventional studies have demonstrated that short-term exercise training programs are effective in patients with moderate-to-severe TBI, though improvement is variable. Inspiratory muscle training is beneficial in other patient populations with diaphragmatic dysfunction, and may be valuable for patients with TBI who have been mechanically ventilated. Thus, clinicians with expertise in cardiorespiratory fitness assessment and exercise training interventions should be included in patient management for individuals with moderate-to-severe TBI. Effects of Workplace-Based Physical Activity Interventions on Cardiorespiratory Fitness: A Systematic Review and Meta-Analysis of Controlled Trials Abstract Background Cardiorespiratory fitness is a strong predictor of all-cause mortality. Physical activity of at least moderate intensity can improve cardiorespiratory fitness. Workplaces may provide a relatively controlled setting in which to improve cardiorespiratory fitness through physical activity. Limited work has been conducted to quantify the impact of delivering physical activity in the workplace on cardiorespiratory fitness. Objective The objective of this systematic review was to quantify the effects of workplace physical activity interventions on peak oxygen consumption (VO2peak) and explore study and participant characteristics as putative moderators. Methods Seven databases were searched up to September 2018. Search terms included “workplace”, “physical activity” and “intervention”. Inclusion criteria were controlled trials where physical activity of at least moderate intensity was delivered in the workplace and compared to controls or non-active comparators; and cardiorespiratory fitness measured by actual or predicted VO2peak. Risk of bias was assessed using the PEDro scale. A random-effects meta-analysis was conducted with between-study variation quantified and then explored for putative predictors with a meta-regression. Pooled estimate uncertainty was expressed as 90% confidence intervals (CIs) and assessed against our threshold value for clinical relevance of 1 mL·kg−1·min−1. Results The final dataset consisted of 25 estimates of VO2peak from 12 trials. The pooled mean differences between intervention and control arms was a beneficial improvement of 2.7 mL·kg−1·min−1 (90% CI 1.6–3.8). The 95% prediction interval ranged from a reduction in VO2peak of − 1.1 to an improvement of 6.5 mL·kg−1·min−1. Between-study heterogeneity (τau) was ± 1.6 mL·kg−1·min−1. The meta-regression showed longer interventions (3.2 mL·kg−1·min−1; 90% CI 1.6–3.8) to have an additive effect and studies with a low risk of bias (− 2.5 mL·kg−1·min−1; 90% CI − 4.0 to − 1.0), and participants of greater baseline VO2peak (− 1.6 mL·kg−1·min−1; 90% CI − 3.6 to 0.4), and age (− 1.4 mL·kg−1·min−1; 90% CI − 3.2 to 0.3) having a lesser effect. Participant sex (percentage female) had an additive effect on VO2peak (0.4 mL·kg−1·min−1; 90% CI − 1.6 to 2.4). Conclusions Workplace-based physical activity interventions consisting of at least moderate-intensity activity improve cardiorespiratory fitness. At the present time, we surmise that no single group of employees (e.g. older employees or less fit individuals) can be definitively identified as standing to benefit more from workplace physical activity interventions than others. This demonstrates the potential utility of workplace physical activity interventions for improving cardiorespiratory fitness in a broad range of healthy employees. Protocol registration: PROSPERO (registration number: 42017057498).