Risk Factors and Multidimensional Assessment of Long Coronavirus Disease Fatigue: A Nested Case-Control Study.

Background: Fatigue is the most prevalent and debilitating long-COVID (coronavirus disease) symptom; however, risk factors and pathophysiology of this condition remain unknown. We assessed risk factors for long-COVID fatigue and explored its possible pathophysiology.

Methods: This was a nested case-control study in a COVID recovery clinic.

Prediction of Maximal Heart Rate in Children and Adolescents.

Objective: To identify a method to predict the maximal heart rate (MHR) in children and adolescents, as available prediction equations developed for adults have a low accuracy in children. We hypothesized that MHR may be influenced by resting heart rate, anthropometric factors, or fitness level.

Design: Cross-sectional study.

Metabolic rate prediction by massless actigraphy for outdoor activities.

Purpose: In military scenarios, there is a need for a system that can enable identification of possible future injury during different activities that are considered to be physically strenuous. The purpose of the present study was to determine whether the use of an octagonal actigraph in conjunction with heart rate (fc) measurements could serve as an accurate method for metabolic rate estimation for different free-living activities in field settings.

Methods: Twenty young healthy volunteers (10 men, 22 +/- 3 years of age, and 10 women, 23 +/- 3 years of age) participated in this study.