The physical fitness and athletic ability survey released by the Japan Sports Agency on October 11 clearly identified a demographic whose physical fitness has declined compared to 25 years ago: women in their 40s. To what extent is ‘no time to exercise’ true? When comparing overseas time-use studies with Japanese daily life data, the answer splits into two depending on the individual.
Fitness increased for those in their 60s, while women in their 40s fell below the level of 25 years ago
The survey collected data from 60,213 people. Comparing the 2025 fiscal year to the 2001 fiscal year (set as 100%), those in their 60s showed a significant increase, with men at 114.1% and women at 118.2%. On the other hand, those in their 40s were at 98.8% for men and 93.6% for women, representing a 6.4% decline for women. Among women aged 35–39 and 45–49, the percentage of those who exercise at least once a week had also decreased.
However, this is cross-sectional data measuring different people each year. The design does not allow for causal claims such as ‘physical fitness declined due to child-rearing.’
‘No time to exercise’ does not hold true on average
Sturm and Cohen (2019) of the US RAND Corporation analyzed 32,048 people from the American Time Use Survey. Free time averaged over 300 minutes per day, and no group fell below 270 minutes. Even so, leisure exercise was 24 minutes for men and 14 minutes for women. No direct relationship was found between free time and exercise volume, leading the authors to conclude that ‘time scarcity cannot explain physical inactivity.’ On average, even if people have time, it is spent on screens (women’s screen time was 175 minutes).
When time poverty crosses a line, exercise is the first to be cut
Meanwhile, Venn and Strazdins (2017) of the Australian National University tracked approximately 5,000 people aged 25–54. Time poverty is a state where time is consumed by work, housework, and caregiving, leaving no time for oneself. This study used a benchmark of over 70 hours per week spent on work, commuting, and caregiving. People who newly fell into this state saw a decrease in exercise, and when combined with financial scarcity, the risk of inactivity more than doubled.
The two are not contradictory. Looking at averages, there is enough time. However, for those who have crossed the line, time is a real factor. So, which side are Japanese women in their 30s and 40s on? According to the Ministry of Internal Affairs and Communications’ Survey on Time Use and Leisure Activities (2021), in households with children under 6, housework-related time is 7 hours and 28 minutes per day for wives and 1 hour and 54 minutes for husbands. For this demographic, I believe ‘no time’ is not an excuse, but closer to a measurable fact.
How far can research on ‘buying time’ go?
Whillans et al. (2017, PNAS) provide a useful reference. They gave 60 working adults $40 for two consecutive weekends; on one weekend, they were asked to spend it on time-saving purchases like housekeeping services, and on the other, on material purchases. On the weekends they bought time, their evening sense of time pressure was lower (4.22 to 3.49), and their positive mood was higher.
However, this study measured mood and time pressure, not exercise volume. It cannot be said that ‘outsourcing housework will lead to exercise.’ All that can be said is that for those in time poverty, what is needed is not ‘motivation,’ but first, measures to reclaim time itself.
As for what works in the stage of ‘continuing’ to exercise after securing time, I covered that in an article using gym data.
Next reading: 21 days is not enough. How many days does it take to form a habit? Insights from data on 30,000 gym members (https://note.com/masaya0408/n/na1e76eedaf37)
