Interval walking training over 10 years protects against age‐associated declines in physical fitness

<jats:sec> <jats:title>Background</jats:title> <jats:p>Exercise training throughout the lifespan is the most effective strategy to prevent age‐associated declines in physical fitness. We assessed the effects of 10‐year continuation of interval walking training (IWT) in older people.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p> One hundred fifty, 30, and 22 men (~68 years) and 333, 112, 85 women (~63 years) started the IWT program in April of 2005, 2006, and 2007, respectively, and thereafter, 36, 13, 7 men and 56, 20, and 16 women had continued the program without intermission until March in 2015, 2016, and 2017, respectively. They were named as the 10‐year IWT group while the rest of them as the dropout group. During the periods, we instructed subjects to perform IWT; repeating ≧5 sets of 3‐min fast walking at ≧70% of peak aerobic capacity for walking (VO <jats:sub>2peak</jats:sub> ), followed by 3‐min slow walking at ~40% VO <jats:sub>2peak</jats:sub> per day, for ≧4 days/week. We measured VO <jats:sub>2peak</jats:sub> and isometric knee extension force (F <jats:sub>EXT</jats:sub> ) before they started the program and every 6 months during the IWT. The target intensities for IWT were re‐adjusted every 6 month according to the current VO <jats:sub>2peak</jats:sub> . We confirmed that subjects in the 10‐year IWT group accomplished the above target throughout the period. For the control group, we adopted the values for the measurements from 208 men and 554 women before starting the program every year regardless of their continuity of the IWT over the 10 years and averaged them crosssectionally every 2 years of the ages from 67 to 77 years for men and 62 to 72 years for women. For the dropout group, in 2017, we recruited subjects who dropped out on the way of the 10‐year IWT to measure the present VO <jats:sub>2peak</jats:sub> , and 29 men and 97 women agreed to participate in the measurement. </jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p> We found that in the control group, F <jats:sub>EXT</jats:sub> decreased linearly along with aging and the decreases were ~30% in men and ~20% in women from the baselines to 10 years later. Similarly, the decreases in VO <jats:sub>2peak</jats:sub> were ~20% in men and women after 10 years. In contrast, in the 10‐year IWT group, F <jats:sub>EXT</jats:sub> decreased along with the following 9.5 years but maintained the higher level than the control group in men and women (P=0.02 and P<0.001, respectively). Additionally, in the 10‐year IWT group, VO <jats:sub>2peak</jats:sub> increased by ~20% for the first 6 month of the IWT and maintained the level along with the following 9.5 years in men and women. As a result, F <jats:sub>EXT</jats:sub> and VO <jats:sub>2peak</jats:sub> in the 10‐year IWT group were ≧20% and ≧40% higher than those of age‐matched subjects in the control group after 10 years (P=0.04 and P<0.001, respectively). In the dropout group, the profile of VO <jats:sub>2peak</jats:sub> before their dropout was similar to that in the 10‐year IWT group, but after the dropout, VO <jats:sub>2peak</jats:sub> decreased at −1.2±0.4% and −1.0±0.2% per year in men and women, respectively, until 2017, significantly greater decreasing rate than the 10‐year IWT group (both, P<0.001), but less than the control group. </jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>IWT over 10 years protected against age‐associated declines in physical fitness in older people and the effect was partially preserved even if they dropped out on the way.</jats:p> <jats:p> <jats:bold>Support or Funding Information</jats:bold> </jats:p> <jats:p>This study was supported by grants from the Japan Society for the Promotion of Science (16K16560, 15H01830).</jats:p> <jats:p> This abstract is from the Experimental Biology 2018 Meeting. There is no full t ...