Exercise training is crucial in the management of nonalcoholic fatty liver disease (NAFLD); however, whether it can achieve clinically meaningful improvement in liver fat is unclear. We investigated the association between exercise training and the achievement of validated thresholds of MRI-measured treatment response. METHODS:Randomized controlled trials in adults with NAFLD were identified through March 2022. Exercise training was compared with no exercise training. The primary outcome was ‡30% relative reduction in MRImeasured liver fat (threshold required for histologic improvement in nonalcoholic steatohepatitis activity, nonalcoholic steatohepatitis resolution, and liver fibrosis stage). Different exercise doses were compared. RESULTS:Fourteen studies (551 subjects) met inclusion criteria (mean age 53.3 yrs; body mass index 31.1 kg/ m 2 ). Exercise training subjects were more likely to achieve ‡30% relative reduction in MRI-measured liver fat (odds ratio 3.51, 95% confidence interval 1.49-8.23, P 5 0.004) than those in the control condition. An exercise dose of ‡750 metabolic equivalents of task min/wk (e.g., 150 min/wk of brisk walking) resulted in significant treatment response (MRI response odds ratio 3.73, 95% confidence interval 1.34-10.41, P 5 0.010), but lesser doses of exercise did not. Treatment response was independent of clinically significant body weight loss (>5%).

Background The Pfizer-BioNTech COVID-19 vaccine uses a novel messenger RNA technology to elicit a protective immune response. Short-term physiologic responses to the vaccine have not been studied using wearable devices. Objective We aim to characterize physiologic changes in response to COVID-19 vaccination in a small cohort of participants using a wearable device (WHOOP Strap 3.0). This is a proof of concept for using consumer-grade wearable devices to monitor response to COVID-19 vaccines. Methods In this prospective observational study, physiologic data from 19 internal medicine residents at a single institution that received both doses of the Pfizer-BioNTech COVID-19 vaccine was collected using the WHOOP Strap 3.0. The primary outcomes were percent change from baseline in heart rate variability (HRV), resting heart rate (RHR), and respiratory rate (RR). Secondary outcomes were percent change from baseline in total, rapid eye movement, and deep sleep. Exploratory outcomes included local and systemic reactogenicity following each dose and prophylactic analgesic use. Results In 19 individuals (mean age 28.8, SD 2.2 years; n=10, 53% female), HRV was decreased on day 1 following administration of the first vaccine dose (mean –13.44%, SD 13.62%) and second vaccine dose (mean –9.25%, SD 22.6%). RHR and RR showed no change from baseline after either vaccine dose. Sleep duration was increased up to 4 days post vaccination, after an initial decrease on day 1. Increased sleep duration prior to vaccination was associated with a greater change in HRV. Local and systemic reactogenicity was more severe after dose two. Conclusions This is the first observational study of the physiologic response to any of the novel COVID-19 vaccines as measured using wearable devices. Using this relatively small healthy cohort, we provide evidence that HRV decreases in response to both vaccine doses, with no significant changes in RHR or RR. Sleep duration initially decreased following each dose with a subsequent increase thereafter. Future studies with a larger sample size and comparison to other inflammatory and immune biomarkers such as antibody response will be needed to determine the true utility of this type of continuous wearable monitoring in regards to vaccine responses. Our data raises the possibility that increased sleep prior to vaccination may impact physiologic responses and may be a modifiable way to increase vaccine response. These results may inform future studies using wearables for monitoring vaccine responses. Trial Registration ClinicalTrials.gov NCT04304703; https://www.clinicaltrials.gov/ct2/show/NCT04304703

Background & Aims Physical activity offers promise to protect against multiple non-hepatic primary cancers. We performed a systematic review to quantify the association between physical activity and hepatocellular carcinoma (HCC) risk. Methods We searched the Cochrane Library, Embase, Medline and trial registries through December 2020 for studies that measured physical activity levels in adults at risk for HCC. The primary outcome was HCC. Subgroup analysis was performed limiting to vigorous physical activity. Proportions and random-effects odds ratios (OR) with corresponding 95% confidence intervals (CI) were calculated. Results Seven studies met inclusion criteria, comprising 777,662 subjects (median age 55 years; 55% female). Greater amounts of physical activity were associated with less HCC (OR 0.65, 95% CI 0.45-0.95, p = 0.03) compared to lower amounts. Vigorous physical activity was associated with even less HCC (OR 0.62, 95% CI 0.49-0.79, p < 0.01). Conclusions This meta-analysis demonstrates that greater amounts of physical activity are associated with lower odds of HCC. These results support the use of regular physical activity as an effective way to prevent HCC and provide helpful data to support a for future exercise-based interventional study to better define the optimal exercise prescription for patients at risk for primary liver cancer.