Better physical fitness may be associated with healthier kidneys, according to a new study from Japan, Knowridge reported, citing research published in the journal Medicine & Science in Sports & Exercise. The study focused on cardiorespiratory fitness – the body’s ability to deliver oxygen during sustained physical activity – and its potential connection with future kidney health, an issue of particular importance for Japan’s rapidly ageing population.
The study involved 198 adults from Ibaraki Prefecture with preserved kidney function. Their physical fitness was measured using a cycling test rather than self-reported activity levels. The researchers then monitored the participants’ kidney function for five years and found that people with higher cardiorespiratory fitness experienced a slower decline in kidney function and were less likely to lose at least 20 per cent of it. The association remained even after the researchers accounted for factors such as age, sex, body composition, smoking and pre-existing conditions.
Possible explanations for the association include healthier blood vessels and better circulation among fitter people, as well as improvements in blood pressure, blood sugar and body weight resulting from physical activity – all factors that can reduce long-term strain on the kidneys. The authors stress, however, that the study was observational and cannot establish a cause-and-effect relationship. Its small sample size and focus on a single Japanese region also mean that the findings need to be confirmed by larger future studies.
Despite these limitations, the five-year follow-up is a significant strength of the study, as it allowed the researchers to observe changes in kidney health over time rather than simply comparing participants at a single point. The scientists emphasise that physical fitness cannot replace established methods of protecting kidney health, such as controlling diabetes and blood pressure, but the findings provide an additional reason to view physical activity as an important part of healthy ageing. | BGNES
