Active cycle of breathing technique

Active cycle of breathing technique

The Active Cycle of Breathing Techniques (ACBT) is an active breathing technique performed by the patient to help clear their sputum the lungs. The ACBT is a group of techniques which use breathing exercises to improve the effectiveness of a cough, loosen and clear secretions and improve ventilation.

ACBT consists of three main phases:

  • -Breathing Control
  • -Deep Breathing Exercises or thoracic expansion exercises
  • -Huffing OR Forced Expiratory Technique (F.E.T)

Additionally, a manual technique (MT) or positive pressure can be added if and when indicated, to create a more complex cycle to help improve removal of secretions on the lungs

Breathing Control

  • -Breathing control is used to relax the airways and relieve the symptoms of wheezing and tightness which normally occur after coughing or breathlesness.
  • -Breathing should be performed gently through the nose using as little effort as possible. If this is not possible then breathing should be done by mouth. If it is necessary to breathe out through the mouth this should be done with ‘pursed lips breathing’.

This technique,will reduce tension, promote relaxation,and also done in between the more active exercises of ACBT as it allows for relaxation of the airways .

Deep Breathing Exercises
Deep breathing is used to get air behind the sputum stuck in small airways:

  • -Relax upper chest.
  • -Breathe in slowly and deeply.
  • -Breathe out gently until lungs are empty – don’t force the air out.
  • -Repeat 3 – 4 times, if the patient feels light headed then it is important that they revert back to the

Breathing Control portion of the cycle.

At the end of the breath in, hold the air in the lungs for 3 seconds (this is known as an inspiratory hold).

Deep breathing/thoracic expansion exercises recruit the collateral ventilatory system assisting, the movement of air distal to mucus plugs in the peripheral airways.

Huffing or FET

  • -The FET is an integral part of the ACBT described by Pryor and Webber .
  • -A huff is exhaling through an open mouth and throat instead of coughing.
  • -Huffing moves sputum from the small airways to the larger airways, from where they are removed by coughing. Coughing alone does not remove sputum from small airways.

Instructions to patient:


  • -Take a medium sized breath in.
  • -Squeeze the breath out fairly hard and fast keeping mouth and throat open. Imagine trying to steam up a mirror or blow a tissue held out in front of you.
  • -Attempt to clear sputum 2-3 times then return to breathing control (Phase one) to relax airways.
  • -Repeat as above except for a larger breath in to remove secretions/sputum in other areas of the lungs.
  • -Post surgical /pain (rib fracture/ICC).
  • -Chronic increased sputum production e.g in Chronic bronchitis, cystic fibrosis.
  • -Acute increase sputum production.
  • -Poor expansion.
  • -Sputum Retention.
  • -Cystic Fibrosis
  • -Bronchiectasis.
  • -Atelectasis.
  • -Respiratory muscle weakness.
  • -Mechanical ventilation.
  • -Asthma.


  • -ACBT can be performed in sitting, lying or side-lying positions.
  • -Initially you should start in a sitting position until you are comfortable and confident to try different ones.
  • -Extensive evidence supports its effectiveness in sitting or gravity assisted positions.
  • -A minimum of ten minutes in each productive position is recommended.
  • -The ACBT may be performed with or without an assistant providing vibration, percussion and shaking. Self percussion/compression may be included by the patient.


By – HOD – Dr Mohammed Aslam Ahmed
Department of Physiotherapy
Uttaranchal (P.G.) College Of Bio-Medical Sciences & Hospital

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