Fidelity, tolerability and safety of acute high-intensity interval training after hospitalisation for COVID-19: a randomised cross-over trial

Abstract

Objectives. Many patients with COVID-19 suffer from persistent symptoms, many of which may potentially be reversed by high-intensity interval training (HIIT). Yet, the safety and tolerability of HIIT after COVID-19 is controversial. This study aimed to investigate the fidelity, tolerability and safety of three different HIIT protocols in individuals that had recently been hospitalised due to COVID-19. Methods. The study was a randomised cross-over trial. We compared three supervised HIIT protocols (4×4, 6×1, 10-20-30) in 10 individuals recently discharged after hospitalisation for severe COVID-19. Each HIIT protocol had a duration of 38 min and was performed with a 1-week washout between them. Outcomes included adverse events, exercise training intensity and tolerability assessed by the Likert scale (1–10). Results. All 10 participants aged 61 (mean, SD 8) years (5 males) completed all three HIIT protocols with no adverse events. High intensities were achieved in all three protocols, although they differed in terms of time spent with a heart rate ≥85% of maximum (mean (SD); 4×4: 13.7 (6.4) min; 10-20-30: 12.1 (3.8) min; 6×1: 6.1 (5.6) min; p=0.03). The three protocols were all well tolerated with similar Likert scale scores (mean (SD); 4×4: 8 (2), 10-20-30: 8 (2), 6×1: 9 (2), p=0.72). Conclusion. Our findings indicate that recently hospitalised individuals for severe COVID-19 may safely tolerate acute bouts of supervised HIIT as per protocol. This warrants future studies testing the potential of regular HIIT as a rehabilitation strategy in this context.

Fidelity and tolerability of two high-intensity interval training protocols in patients with COPD: a randomised cross-over pilot study

“…In the 10×1 HIIT protocol, the success criteria were to complete a minimum of 8 intervals at 100% of W max . If the patients failed to keep the pace >60 RPM for more than 5 s, the workload was reduced by 10% from the next interval 25…”

“…If the training session achieved a red rank, the session was considered unacceptable, where an amber ranking was considered applicable with precautions. If the HIIT session achieved a green rank, the session was considered acceptable and feasible 25 27…”

“…If the patients failed to keep the pace >60 RPM for more than 5 s, the workload was reduced by 10% from the next interval. 25 At the end of each HIIT session, tolerability was evaluated by the patient's subjective perception of tolerance using a 10-point Likert scale. 26 Immediately after the HIIT session, the patient was asked to what degree he or she agreed with the following statement: 'How tolerable was today's training?'…”

“…To achieve a formal comparison of the two HIIT protocols that accounted for both fidelity and tolerability, we used a red-amber-green System (figure 2), based on a similar rating system used in a recent study. 25 This was based on (1) the patients' adherence to the protocol, which encompassed completed training volume and intensity as indices of fidelity and (2) a 10-point Likert Scale-based assessment of perceived tolerability. The completed training volume was evaluated as minutes completed in percent of prescribed in both protocols.…”

Effects of Aerobic Training in Patients with Subacute COVID-19: A Randomized Controlled Feasibility Trial

“…A recent review has underlined that the studies conducted propose intervention programs that are not RCTs and are highly heterogeneous: The described aerobic exercises involved different modes of aerobic training, different durations ranging between 5 and 30 min, and intensities assessed in different ways or not always reported [ 24 ]. For example, while Foged et al [ 25 ] reported the safety of performing three bouts of high-intensity interval training in individuals recently recovered from severe COVID-19, Mohamed and Alawna [ 26 ] indicated that 2 weeks of moderate-intensity aerobic training decreased the severity of symptoms and improved immune functions in young adults with mild to moderate COVID-19. More recently, Araújo et al [ 27 ] found that a cardiopulmonary rehabilitation program consisting of continuous moderate-intensity aerobic and resistance training in patients with severe COVID-19 improved respiratory muscle strength, lung function, exercise tolerance, fatigue, and quality of life.…”