Is it advisable for a patient with primary spontaneous pneumothorax history to continue strength training? does it increase the risk at all?

Possibly: Non-trauma, spontaneous pneumothorax (sp) occur as a result of an abnormality in the lung tissue. Risk factors for sps include: smoking (including marijuana), tall thin stature in otherwise healthy, connective tissue disorders, pregnancy, familial history. Sps are associated with 20-40% recurrence(depending type). Valsalva/increased intrathoracic pressure can cause bleb rupture.

Live your life: Spontaneous pneumothoraces usually occur in tall, skinny men. But not exclusively. That being said, there is a defined risk of recurrence. If you have had it only once, often we will recommend waiting for a recurrence before doing surgery. The surgery is minimally invasive and the recovery very quick. Live your life, if it recurs you'll have it fixed. Do not alter your life in fear of this.