| Study | Reason for exclusion |
|---|---|
| Boukelia 2017 | Did not investigate acute respiratory infection; authors investigated diurnal physiological and immunological responses to exercise |
| Colburn 2018 | Investigated adjuvants to seasonal influenza vaccine |
| Couto 2014 | Investigated swimming on airway inflammation in a longitudinal study |
| Crabtree 2015 | Investigated effects of exercise in the cold on ghrelin, PYY, and food intake, and not ARI |
| Dubnov‐Raz 2015 | Investigated effects of vitamin D supplementation on upper respiratory tract infections in adolescent swimmers, focusing on supplementation and not exercise |
| Edwards 2015 | Investigated effects of exercise prior to influenza vaccination |
| Fujimaki 2017 | Investigated effects of exercise for glottal incompetence to improve vocal problems to prevent aspiration pneumonia in the elderly |
| Johansson 2017 | Investigated the effects of physical therapy treatment on impaired chest mobility and respiratory movement in patients with airway environmental sensitivity, not ARI |
| Killer 2015 | Investigated the effects of hydration status during prolonged endurance exercise on salivary antimicrobial proteins, not ARI |
| Komano 2018 | Investigated the effects of heat‐killed Lactococcus lactis JCM 5805 on high‐intensity exercise, focus was the supplementation |
| Kulnik 2014 | Investigated respiratory muscle training to improve cough and reduce the incidence of pneumonia in acute stroke, not ARI |
| Kunz 2015 | Investigated the effect of fitness level on salivary antimicrobial protein responses to a single bout of cycling exercise, not RCT |
| Kurowski 2014 | Investigated serum Clara cell protein CC16 with respiratory infections and immune response to respiratory pathogens in elite athletes; not an RCT |
| Langeskov‐Christensen 2015 | Investigated aerobic exercise to alleviate flu‐like symptoms following interferon beta‐1a injections in patients with multiple sclerosis, not ARI |
| Lee 2015 | Investigated the effects on immunoglobulin and changes of physiological stress and physical fitness level induced by increased cold stress, not an RCT |
| Morgado 2018 | Investigated if long‐term swimming training modifies acute immune cell response compared to a high‐intensity session, not an RCT |
| Morris 2016 | Investigated standardised rehabilitation and hospital length of stay amongst patients with acute respiratory failure, not ARI |
| Nieman 2014 | Investigated the effects on immune and inflammation responses of a 3‐day period of intensified running versus cycling, there was no non‐exercise control group |
| Oliveira 2016 | Investigated respiratory physiotherapy for patients who had lower respiratory tract infections |
| Qieqeshlaq 2016 | Investigated high‐intensity intermittent training and consumption of probiotic supplement on immune cells; study focused on supplementation |
| Rocco 2018 | Systematic review; not an RCT |
| Shing 2007 | Investigated the effect of dairy‐based beverages after exercise; study focused on supplementation |
| Strasser 2016 | Investigated probiotic supplementation in trained athletes, RCT focusing on probiotics and not exercise |
| van Middendorp 2016 | Investigated healthy men after a training programme consisting of meditation, breathing techniques, and exposure to cold; RCT focusing on multimodal interventions and not ARI |
| Vaz Fragoso 2016 | Investigated the effect of structured physical activity on respiratory outcomes in community‐dwelling elderly adults with mobility limitations, RCT focusing on breathing capacity and not ARI |
| Witard 2014 | Investigated high‐protein diet and exercise, RCT focusing on supplementation |
ARI: acute respiratory infection HRV: human rhinovirus type 16 PYY: peptide YY RCT: randomised controlled trial