You can control the tensions via respiration.

The battle against those tensions of yours by controlling your respiration.

Previously I have discussed physical relaxation, yawning and stretching, and if you have been practising the exercises I described they will have gone a long way towards the breaking up of tension. Let's move on now. Your next task is to learn how to develop and control your respiration. Yoga breathing, at its best, employs five ideas:
Using your lungs to their whole capacity. Retention of the breath. Cleansing of the lungs and bronchial passages.
Breathing and slow stretching.
Alternate breathing, or breathing through one nostril at a time. It is called "Sun and Moon" breathing.
We will cover all five principles of Yoga breathing.
Firstly, then, practise the Yoga Complete Breath as often as you can and always remember that the depth and quality of your breathing is far more important than the number of breaths you take.
It is recommended that you begin your Pranayama or breathing exercises with a couple of full breaths in order to clean out your lungs and to get ready for the other breathing exercises, all of which are fundamentally variants of the Complete Breath. You may practise the Complete Breath in a range of positions according to taste: you can do it either standing up straight, sitting on a hard chair while holding your hands in your lap, lying on the floor, or sitting on it with a straight back.
Retention of the Breath
This should not be attempted until you are able to perform the Complete Breath at least half a dozen times in succession without experiencing any unpleasant dizziness or fainting. Then proceed as follows. Breath in deeply and hold the breath for a couple of seconds before exhaling. For initial a moment is sufficient, but steadily increase the time of withhold till you are able to do it for many seconds with no trouble and application of extra effort. Take it easy and feel into your lungs. Do not try to force them to do something that they are clearly trying to tell you is uncomfortable. Remember that correct Yoga breathing is based on the body's natural impulses. At the end of every exhalation there is a natural pause with the lungs completely empty. At first you must obey this natural impulse and breathe in when you feel the need to, but gradually extend this pause for a second longer, and then yet another second, but do not force the pace.
This gradual extension of the pause will make the ensuing inhalation that much more full and deep. Practise retention of the breath until you can perform it to your satisfaction but I repeat s-l-o-w is the word for Yoga breathing, slow and rhythmic. The word hurry has no place what so ever.