Apnea walking. 30 Steps hold, 30 steps breathe. Three rounds after inhale, normal exhale, full exhale. 45 Steps hold, 45 steps breathe. Three rounds after inhale, normal exhale, full exhale. 60 Steps hold, 60 steps breathe, Three rounds after, inhale, normal exhale, full exhale. 75 Steps hold, 75 steps breathe. Three rounds after inhale, normal exhale, full exhale.