## 2 Main Content of the Special Issue
We organized the different papers according to their contributions to the main parts of the monitoring and control engineering scheme applied to human health applications, namely papers focusing on measuring/sensing of physiological variables [24; 25; 26; 27; 28; 29; 30; 31], contributions describing research on the modelling of biological signals [32; 33; 34; 35; 36; 37; 38], papers highlighting health monitoring applications [39; 40; 41; 42], and finally examples of control applications for human health [43; 44; 45; 46; 47; 48]. In comparison to biomedical engineering, we envision that the field of human health engineering also covers applications on healthy humans (e.g., sports, sleep, and stress) and thus not only contributes to develop technology for curing patients or supporting chronically ill people, but also for disease prevention and optimizing human well-being more generally. The first series of articles in this SI describes methods for (improved) measuring, sensing, or communication of physiological signals. The work of [PERSON] et al. [24] contributes to solving the problem of gradient artefacts (GA) in electroencephalography (EEG) signals when measured in combination with functional magnetic resonance imaging (fMRI) in MR scanners. They demonstrated that the use of realistically human head-shaped phantoms outperformed the standard used spherical phantoms for the characterization of GA in EEG data and thus improves the GA removal in the signal post-processing step. [PERSON] et al. [25] investigated the usability of four different types of interfaces (text, diagram, image, and animation) for wearable devices with health management applications (app) for elderly people. Their research demonstrated that most (older as well as younger) users preferred animation interfaces for communicating health information, but that older adults, in contrast to younger users, were also open to text interfaces. Such research can contribute significantly to the development of useful health management apps for the growing elderly population. [PERSON] et al. [26] developed a method for continuously measuring systolic blood pressure (SBP) using photoplethysmography (PPG) sensing elements. Since their method is based on cheap PPG sensing elements that can be integrated in wearables, this approach can significantly contribute to (preventive) health monitoring as, compared to classical (expensive) cuff-based methods, as it allows 24/7 measurements. The work of [PERSON] et al. [27] describes the use of a nine-zone thermal manikin head for measuring convective and evaporative heat losses from a human head wearing a bicycle helmet. They demonstrated that the design of the helmet, mainly characterized by the number and position of vent openings and the presence of internal air channels, has a significant effect on the heat losses of a human head when covered by a bicycle helmet. The results of this work demonstrate the use of thermal manikins for improving comfort and safety of cycling activities. In their work, [PERSON] et al. [28] studied the effect of squat lifting versus stoop lifting in terms of joint and muscle loading when handling heavy materials. Their study demonstrates that squat lifting imposes higher peak full body musculoskeletal loading compared to stoop lifting, but similar lower back loading, which is an important factor in work-related musculoskeletal disorders (WMSDs). These results show the usefulness of 3D movement trajectory and force analysis in combination with electromyography for optimizing ergonomic guidelines. [PERSON] et al. [29] studied the effects of in-shoe foot orthosis contours on heel pain due to calcaneal spurs. The applied method made use of force sensors for measuring 2D pressure information on the foot in combination with an alogmeterfor quantifying pain. By combining these measurements the authors were able to optimize inside geometry resulting in improved comfort by significantly reducing pain. In their work, [PERSON] et al.