A wearable system comprises tourniquets. Each of the tourniquets comprises an inflatable chamber, and is configured to occlude blood flow in an artery of a wearer. The wearable system comprises compressed gas sources in fluid communication with the inflatable chamber of the tourniquets. The wearable system comprises valves. Each of the valves comprises an input in fluid communication with one of the compressed gas sources, and an output in fluid communication with the inflatable chamber of one of the tourniquets. The wearable system comprises fixed pressure regulators. Each of the fixed pressure regulators is in fluid communication with the valves, and is configured to regulate a pressure of the compressed gases delivered to the inflatable chamber of at least one of the tourniquets. The wearable system comprises switches. Each of the switches is configured to operate one of the valves.