Suffering, dejection, trembling, inhalation, and exhalation accompany the distractions.

Bryant Commentary:

Accompanying the disturbances noted in the previous sūtra is a further set of secondary disturbances of the mind which, as always, the commentators explain individually. Vyāsa refers to the three standard sources of suffering or pain, duḥkha, the first item on Patañjali’s list, recognized in Hindu knowledge systems (e.g., Sāṅkhya Kārikā I.1), which will be discussed in II.15: suffering from one’s own body and mind, suffering from other entities, and suffering from the gods, that is, from nature. Vācaspati Miśra gives disease as an example of suffering from one’s own body, and desire as suffering of the mind (or, for Rāmānanda Sarasvatī, romantic love!); a tiger’s mauling as an example of pain from other living entities, and planetary influences as an example of suffering from nature (which includes natural effects such as excessive heat and cold). Vijñānabhikṣu notes that these three categories are not comprehensive since they do not include pain arising from items such as pots and cloth, by which he seems to be referring to pain caused by inanimate objects. Pain, says Vyāsa, is essentially that which living beings attempt to avoid, as Patañjali will state in II.16. (The ability to perceive the pervasiveness of suffering is discussed in some detail in II.15, since it is an essential prerequisite for undertaking the spiritual path.)

Dejection, daurmanasya, the second item on the list, is the disturbance of the mind that arises when one’s desires are obstructed. Trembling, aṅgam–ejayatva, is self-explanatory, that which causes the limbs to shake, and which, according to Bhoja Rāja, interferes with one’s āsana, yogic sitting posture. Inhalation, śvāsa, is the excessive intake of external air, which Vācaspati Miśra specifies is a defect when it occurs involuntarily and interferes with the prāṇāyāma breathing technique known as recaka. Vyāsa glosses exhalation, praśvāsa, with expelling gas, which, again, Vācaspati Miśra specifies is a defect when it occurs involuntarily and interferes with the prāṇāyāma breathing technique known as pūraka.

Thus, the nine disturbances mentioned in I.30 are not only disruptions to the practice of yoga in their own right, but they produce a further set of disruptions. Vyāsa states that although these symptoms accompany the nine disturbances, they do not manifest for the yogī whose mind is fixed. Such obstacles disappear when the mind is not distracted, and consequently a person who has control over the mind does not experience pain and dejection, etc. Ultimately, according to Patañjali in I.29, they all disappear by devotion to Īśvara.

Sorrow, Dejection, Restlessness Of Body, Inhalation And Exhalation Arise From (Previous) Distractions.

When they do, one may experience distress, depression, or the inability to maintain steadiness of posture or breathing.

Accompanying these distractions are suffering, frustration, restlessness, and disturbed inhalation and exhalation.

(Mental) pain, despair, nervousness and hard breathing are the symptoms of a distracted condition of mind.

Taimini Commentary:

After enumerating in the last Sutra those conditions which cause Viksepa the author gives in this Sutra a number of symptoms by which the presence of Viksepa can be recognized. The first of these is pain. The presence of pain either physical or mental always shows some serious defect or disharmony in the vehicle. Physical pain is a sign of positive disease while mental pain shows definitely that the mind is not in a natural healthy state. It is either in a state of inner conflict, torn between opposite desires or under the domination of Klesas. Pain is an indication provided by Nature to bring to the notice of the person concerned that all is not well with him. But while most people would run to a doctor if there is any physical pain very few people think of having their mind examined or examining it themselves even when they are suffering excruciating mental pain. But that is what is needed really.

When pain is combined with a consciousness of impotence or incapacity to remove it effectively it leads to despair, despair then leads to nervousness which is merely an outer physical symptom of despair. Nervousness when it reaches a certain degree of intensity disturbs the breathing because it disorganizes the flow of Pranic currents. So these four symptoms really represent the four stages which follow one another when the mind is in that undesirable condition which causes Viksepa.

Since they are mere symptoms the proper way to deal with them is to treat the mind for the fundamental disease which afflicts it. And this will involve a long and tedious course of discipline of our whole nature because all parts of our nature are inter-related. The whole problem of human suffering and misery has been dealt with in Section II by Patanjali in a masterly manner in his theory of Klesas. It will be clear to anyone who has understood this theory that there can be no cheap but effective solution of the problem of human suffering except through the conquest of the Great Illusion. As long as this is not achieved and the mind remains subject to the illusions of the lower life, suffering and misery must remain and the outer symptoms which reflect the disordered condition of the mind must continue to appear in greater or lesser degree.

But as has been pointed out already Patanjali is not dealing here with the fundamental problem of human suffering and misery but with those particular conditions of the mind which produce Viksepa and interfere with the practice of Dharana, Dhyana and Samadhi. This problem is of a more limited nature and has to be tackled by adopting means of more limited and specific nature. These are dealt with in the following eight Sutras. 

Sorrow, despair, unsteadiness of the body and irregular breathing further distract the citta.

Iyengar Commentary:

Besides the obstacles mentioned in I.30, there are four more causes of distraction: sorrow, despair or evil disposition, tremor of the body and irregular or laboured breathing. (Possibly, laboured breathing shakes the body, creating instability, which in turn brings mental distress.) These cause further distractions which agitate the mind and consciousness.

These impediments are of three types: self-inflicted (adhyatmika), imbalances of elements in the body (adhibhautika) and problems brought about by fate, e.g. genetic defects (adhidaivika). They need to be fought and conquered through yogic disciplines (see I.6; II.3, 17, 34).

Accompaniments to the mental distractions include distress, despair, trembling of the body and disturbed breathing.

Satchidananda Commentary:

 These are symptoms that we all sometimes experience which prevent concentration and meditation. That is where we have to take care of our day-to-day activities, movements, associations and diet. We shouldn’t allow the body and mind to be tamasic. They should always be in a sattvic (tranquil) condition. That cannot be created all of a sudden by meditation alone, so we have to take care of all these things in our daily life. A sickly body can never be fit to sit; it will not allow the mind to meditate quietly. Weak nerves will always create tremors. When some people meditate, they tremble and perspire. These are symptoms of physical weakness. But such things will not happen if we keep our body in proper condition by right diet, exercise, proper rest and if we do not allow it to be lazy or dull.

Grief, mental distress, tremor of the body and irregular breathing, accompany non-retention of concentration.

SV Commentary:

Concentration will bring perfect repose to mind and body every time it is practised. When the practice has been misdirected, or not enough controlled, these disturbances come. Repetition of Om and self-surrender to the Lord will strengthen the mind, and bring fresh energy. The nervous shakings will come to almost everyone. Do not mind them at all, but keep on practising. Practice will cure them, and make the seat firm.

Pain is either from one’s self, or from external terrestrial objects, or from the powers of nature. Pain is that affected by which people try to do away with it.

Despair is the condition of the mind consequent upon the nonfulfilment of some desire.

Shakiness is that which causes the organs to shake.

Inspiration is the action of the life-force drinking in external air.

Expiration is that which throws out the internal gas.

These are the companions of the distractions of the mind. They appear in him whose mind is distracted. They do not exist in him whose mind is entranced.

~ Rāma Prasāda translation.