Ulrik Wisløff

At a glance

• Ulrik Wisløff is a Norwegian exercise physiologist, professor and entrepreneur. He heads the Cardiac Exercise Research Group (CERG) at the Norwegian University of Science and Technology (NTNU) in Trondheim.
• He is known for ‘4x4’ interval training: four bouts of four minutes of hard effort at roughly 85 to 95 percent of maximum heart rate, each followed by three minutes of active recovery.
• As early as 2007 his team showed that interval training improved fitness in heart-failure patients more than moderate continuous training.
• Using data from Norway’s large HUNT study he developed an online ‘fitness age’ calculator based on estimated maximal oxygen uptake (VO2max).
• In the Generation 100 study (BMJ, 2020), more than 1,500 Norwegians aged 70 to 77 trained for five years. There was no significant difference in mortality, but a favourable trend in the interval group.
• For longevity, his work matters because fitness is one of the strongest predictors of health in later life.
• Takeaway: add one 4x4 session a week, for example walking uphill or cycling, at an intensity that suits you.