How higher fitness levels cut the risk of bladder and kidney cancer, according to a 22-year study

According to the European Medical Journal, adults with higher cardiorespiratory fitness may have a significantly lower risk of developing urinary tract cancers, including bladder and kidney cancer. These findings come from the second Trøndelag Health Study, or HUNT2, and provide strong evidence that better fitness could offer long term protection, particularly for men.Data from 46,968 adults followed for a median period of 22.2 years were analyzed. Researchers estimated each participant's cardiorespiratory fitness by using a validated model that took into account factors such as age, waist circumference, resting heart rate, and levels of physical activity. Participants were then sorted into one of three groups: low, medium, or high fitness. Over this follow-up period, incident urinary tract cancers were ascertained using cause-specific Cox proportional hazard models. In their analysis, a clear protective effect was seen to be associated with better cardiorespiratory fitness.Compared with adults in the low fitness group, participants with medium fitness showed a 13 percent lower risk of developing urinary tract cancers. Those in the high fitness group saw a substantial 36 percent reduction.The effect was even more striking in men: medium fit men had a 17 percent lower risk and highly fit men had a 41 percent lower risk for these cancers over the two decade follow-up period.When researchers analyzed cancer types separately, they saw some significant sex differences: high fitness in men was linked to a 34 percent lower risk of bladder cancer. In women, no such link was found.The investigation found a significant inverse dose-response relationship between kidney cancer and cardiorespiratory fitness. Simply stated, the higher the cardiorespiratory fitness, the lower the risk of developing kidney cancer. Additionally, this trend was more prominent in men; therefore, high fitness may be particularly protective in male subjects.Although this study is observational and cannot establish a direct causal relationship, several factors strengthen the findings: the large sample size, the long duration of follow up, and consistent dose response patterns across cancer types.Researchers point out that estimated cardiorespiratory fitness is an easily accessible, practical measure that can be included in routine health examinations. Determining individuals with poorer fitness might provide clinicians with an insight into those individuals at higher risk of developing urinary tract cancers.The findings show that promoting physical activity and enhancing cardiorespiratory fitness may have greater benefits. It follows, therefore, that active lifestyle changes, including regular aerobic exercise, can help reach a healthy waist circumference and manage resting heart rate to lower cancer risk in the long term. Indeed, as the evidence accrues, cardiorespiratory fitness may become one of the important clinical markers for the prediction of cancer risk and personalized prevention strategies.