Norwegian 4x4 Protocol

The Norwegian 4x4 Protocol is a groundbreaking high-intensity interval training (HIIT) method designed to maximize cardiovascular health and endurance. This method involves four intense four-minute intervals at 90-95% of your maximum heart rate, each followed by a three-minute active recovery period. Backed by scientific research, the 4x4 Protocol is renowned for significantly boosting VO2 max, a critical measure of aerobic capacity.