HIIT + tech upgrade
New reviews reaffirm HIIT's edge for brain (BDNF) and vascular (VEGF) gains — especially in overweight people — and Norwegian‑style HIIT routines are trending for cognitive and metabolic benefits ( ). At the same time, the Amazfit Active 3 got a v3.7.0.8 firmware update that adds more precise lactate‑threshold tracking to help athletes time intervals and recovery (gadgetsandwearables.com).
A new Frontiers systematic review published 22 January 2026 screened 39 studies and reported that acute HIIT produced larger changes in exerkines including BDNF and VEGF compared with lower‑intensity exercise, with 14 studies classified as acute effects and 22 as chronic. (frontiersin.org) A 2023 network meta‑analysis that pooled 22 randomized trials and 656 participants found an acute peripheral BDNF increase for HIIT versus control with a network standardized mean difference (SMD) of 1.49 (95% CI 0.61–2.38), supporting a robust short‑term biomarker response. (onlinelibrary.wiley.com) A 2024 Scientific Reports meta‑analysis of 20 RCTs quantified cognitive gains from HIIT: information processing (SMD 0.33), executive function (SMD 0.38) and memory (SMD 0.21), with subgroup analyses showing different benefits by age and intervention length. (nature.com) The Norwegian 4×4 protocol—developed at NTNU by researchers including Ulrik Wisløff, Jan Helgerud and Jan Hoff—prescribes a ~10‑minute warm‑up followed by four 4‑minute efforts at roughly 85–95% HRmax separated by ~3 minutes active recovery, and is repeatedly cited as the model behind recent Norwegian‑style HIIT trends. (ntnu.edu; themanual.com) Wisløff’s landmark randomized trial in Circulation (2007) reported VO2peak rose ~46% with high‑intensity interval training versus ~14% with moderate continuous training in post‑infarction patients after 12 weeks, and also showed reverse left‑ventricular remodeling and improved endothelial function. (ahajournals.org) Systematic reviews focused on people with overweight/obesity find consistent metabolic benefits from HIIT—one 2024/2025 review reported HIIT reduced body fat and improved aerobic capacity in about 93% of included trials—while recent nutrition/exerkine reviews highlight adiponectin and other adipokines as responsive biomarkers under active investigation. (mdpi.com; frontiersin.org) Zepp Health began a phased global rollout of firmware v3.7.0.8 for the Amazfit Active 3 Premium on March 22, 2026, delivering a 16.40MB package that flips lactate‑threshold auto‑detection on by default and reorders the workout menu to surface Hybrid Training higher in the list. (gadgetsandwearables.com; chinesesmartwatches.com)
