TABLE 1.

Summary of studies with slow-paced breathing that target variables that are relevant in the context of the COVID-19 pandemic.

Study	Relevant dependent variable	Relevant findings with effect sizes1	Biofeedback	Target population	Sample size
Bernardi et al., 2001	Hypoxia, hypercapnia, and baroreflex sensitivity	SPB reduced the chemoreflex response to both hypoxia and hypercapnia	No	Healthy adults	15
Bernardi et al., 1998	Oxygen saturation and exercise performance	SPB reduced dyspnea and improved both resting pulmonary gas exchange and exercise performance	No	Chronic heart failure patients and healthy adults	61
Bilo et al., 2012	Ventilation efficiency for oxygen	SPB increased blood oxygenation and reduced systemic and pulmonary arterial pressure	No	Healthy adults	Experiment 1: 39; Experiment 2: 28
Laborde et al., 2019a	SSQ and CVA	SPB increased subjective sleep quality (d = 0.51) and increased overnight-CVA (d = 0.68) as well as morning-CVA (d = 0.42)	No	Healthy adults	64
Laborde et al., 2019b	Adaptation to psychological stress after physical exertion and CVA	SPB led to better Stroop interference accuracy (ηp2 = 0.170) after physical exertion	No	Young adults	Experiment 1: 60; Experiment 2: 60
Laborde et al., 2016	CVA	CVA was higher during SPB compared to control (d = 0.35)	No	Adolescents with intellectual disability	17
Paul and Garg, 2012	Anxiety, CVA, and sports performance	SPB reduced both trait and state anxiety, increased CVA (HF), and increased sports performance (dribbling, shooting, and passing)	Yes	Basketball players	30
Pusenjak et al., 2015	Self regulation (heart rate, galvanic skin response, and coherence)	HR during stress tasks was better in SPB group than control.	Yes	Athletes	39
Wells et al., 2012	CVA and stress reaction	SPB after stressor increased HF (ηp2 = 0.122)	Yes	Trained musicians	45

Notes. ¹Wherever reported. CVA, cardiac vagal activity; SPB, Slow-paced breathing; SSQ, Subjective sleep quality; HRV, Heart rate variability; and HF, High frequency.