The Norwegian 4x4 protocol (four 4-minute intervals at the maximum sustainable intensity) is one of the most effective methods for improving VO2 max, which is a major indicator of longevity and long-term health.

noli's read

Scientific literature widely supports the link between high VO2 max and a significant reduction in all-cause mortality, as indicated by several observational studies and meta-analyses (e.g., Mandsager et al., JACC). The 4x4 protocol is a well-documented high-intensity interval training (HIIT) method; randomized controlled trials (RCTs), particularly those conducted by the Wisloff research group, have demonstrated its superiority for improving aerobic capacity compared to moderate-intensity continuous training. The claim is consistent with current science, although it should be noted that 'maximum sustainable intensity' requires a certain level of experience to be gauged correctly without the risk of excessive fatigue. The goal is not to aim for total exhaustion from the first minute, but for a sustained pace that is difficult to maintain over the 4 minutes. In summary, the advice is scientifically robust and constitutes a proven strategy for optimizing cardiorespiratory health.

the sources

1. 1Milanović Z, Sporiš G, Weston M 2015
2. 2Mandsager K, Harb S, Cremer P, Phelan D, Nissen SE, Jaber W 2018