A portable life support system includes a primary oxygen supply in thermal communication with a recirculated ventilation flow from a user. The primary oxygen supply has a solid adsorbent bed made of a molecular sieve that adsorbs oxygen at cryogenic temperatures and desorbs oxygen when heated. The primary oxygen supply freezes carbon dioxide and moisture in the recirculated ventilation flow. A wire mesh is adjacent to the primary oxygen supply to contain frozen carbon dioxide and moisture. A first ice chest is downstream of the primary oxygen supply to condition the temperature and humidity of the recirculated ventilation flow. A liquid cooled garment associated with the suit is in thermal communication with the first ice chest. A ventilation loop receives and delivers the recirculated ventilation flow to the primary oxygen supply, as well as delivers the recirculated ventilation flow from the first ice chest to the suit, whereby pneumatic pressure is supplied to the suit and metabolic oxygen is supplied to the user. A coolant loop is in communication with the liquid cooled garment and first ice chest to regulate suit temperature.