Cross-sectional association of physical activity levels with risks of sarcopenia among older Taiwanese adults – BMC Geriatrics

In Taiwan, this is the first national study to investigate the association between physical activity levels and the risk of sarcopenia in older adults, as recommended by the WHO 2020 guidelines on physical activity and sedentary behavior. The main finding is that physical activity levels exceeding the guidelines appear to be more effective in preventing sarcopenia, especially in the case of older adults engaging in a large number of moderate-intensity activities or for females. An insufficient physical activity level, on the other hand, may lead to an increased risk of sarcopenia, particularly in the case of inadequate moderate activities or for males. These unique findings are informative for policymakers and intervention designers.

This study has four critical implications.

Firstly, in terms of participant characteristics, this study conducted a rapid screening of muscle function using the SARC-F questionnaire, which is recommended by both the European Working Group on Sarcopenia in Older People (EWGSOP) and the Asian Working Group for Sarcopenia (AWGS) [7, 9]. The results identified that the proportion of participants at risk of sarcopenia (score ≥ 4) was 7.3%. According to a 2017 National Health Interview Survey in Taiwan, 7.0% of 2,163 community-dwelling residents aged 65 and above were also likely to have sarcopenia using the SARC-F [40]. Both rates of risk sarcopenia fall within the range reported in previous literature for the prevalence of sarcopenia among Older Taiwanese Adults (3.9–7.3%) [11, 12]. Additionally, there are differences in overall physical activity levels between populations with and without the risk of sarcopenia. Residual analysis showed that those at risk of sarcopenia had lower physical activity levels compared to those without risk, aligning with the findings of a five-year longitudinal study [41], which indicated that older adults with higher activity levels have a significantly lower incidence of sarcopenia. The noteworthy aspect of this study is that the overall physical activity level of older adults in Taiwan is quite active, with 68.3% exceeding the WHO’s recommended physical activity levels per week. Compared to other countries, the study indicates that 15.7% of Taiwanese adults over 65 are physically inactive, which is less than the inactivity prevalence of 31.2% in American and 50% in Australian older adults [42, 43].results show that the risk of sarcopenia is significantly higher in females than in males.

Secondly, the results of overall physical activity levels with risks of sarcopenia among older adults. The results indicate that insufficient physical activity may increase the risk of developing sarcopenia, consistent with previous literature reviews [21,22,23,24]. Conversely, physical activity is beneficial in lowering the prevalence of sarcopenia in older adults [21, 25, 34, 44]. This finding aligns with the previous systematic review and meta-analysis study [21], confirming that physical inactivity is a significant risk factor for sarcopenia in older adults and that increasing physical activity levels effectively protects muscle mass and prevents sarcopenia. Another key finding of this study is that physical activity levels exceeding the guidelines might effectively reduce the risk of sarcopenia. This may be related to the fact that physical activity can increase muscle strength and muscle mass, and improve physiological function in older adults [25, 27, 28, 34]. Although the WHO increased activity level recommendations in 2020, engaging in even higher levels of physical activity may further reduce the risk of sarcopenia. Few studies have explored physical activity levels exceeding these guidelines in the past. According to a cross-sectional study [14], higher levels of physical activity are associated with approximately half the odds ratio for sarcopenia, highlighting physical activity as a key factor in reducing the risk of sarcopenia. While the World Health Organization strongly recommends maintaining physical activity levels within a range that is beneficial for health, this study supports the moderate evidence mentioned by WHO that activity levels beyond the guidelines could provide additional health benefits for older adults [32, 33].

Thirdly, the study investigates the relationship between different intensities of physical activity and sarcopenia. The findings indicate that moderate-intensity physical activity has a similar association with the risk of sarcopenia as overall activity levels. However, this study finds no significant association between vigorous physical activity and an increased or decreased risk of sarcopenia. This lack of statistical difference is likely due to the small number of participants at risk of sarcopenia who engaged in vigorous physical activities at levels sufficient to meet or exceed the recommended guidelines. Only one out of the 43 participants who met the guidelines was at risk of sarcopenia, resulting in a larger confidence interval for this group. Specifically, older adults engaging in less than 150 min per week of moderate-intensity activity may significantly increase the risk of sarcopenia. Conversely, exceeding 300 min per week of such activities may reduce the risk of developing sarcopenia by 62%. These findings align with previous research [29,30,31]. A previous study conducted a three-month intervention in older females, demonstrating that moderate-intensity exercise effectively improves body composition, induces physical changes, and reduces oxidative damage [29]. This plays a crucial role in preventing or treating muscle loss in older adults. In a five-year longitudinal study [31], which objectively measured the physical activity of older Japanese adults using accelerometers, it was found that those walking at least 7,000 to 8,000 steps per day or engaging in at least 15 to 20 min of daily exercise at an intensity greater than 3 METs significantly lowered their risk of muscle loss. This highlights the importance of moderate-intensity activities for older adults.

Finally, this study conducted a sensitivity analysis based on gender. Regarding the gender-specific risks for sarcopenia, it was found that insufficient physical activity is closely related to an increased risk of sarcopenia in older Taiwanese males, while it is less associated with older females. However, physical activity levels exceeding the guidelines in older males did not show a significant correlation with the risk of sarcopenia; conversely, for females, physical activity levels that exceed the guidelines significantly reduced the risk. These results suggest that the relationship between physical activity levels and the risk of sarcopenia may vary by gender. Insufficient physical activity is a significant risk factor for sarcopenia in older adults of both genders, but physical activity levels exceeding the guidelines may significantly prevent sarcopenia in females. These findings align with the previous systematic review and meta-analysis study [21], which found that physical activity significantly reduces the odds of suffering from sarcopenia, with a more substantial overall effect size in males (Z = 6.50) compared to females (Z = 3.79).

There were several limitations to this study. First, this study used a cross-sectional design and was unable to establish a causal relationship between physical activity and the risk of sarcopenia, establishing only an association. Despite this, such a design is appropriate for encompassing a wide range of older adults within a short period, thereby allowing an initial exploration of the association between the two. Secondly, the study uses self-reported questionnaires and telephone surveys to measure participants’ behavior and the risk of sarcopenia, which could have resulted in recall bias or the potential risk of social expectation bias; however, the IPAQ-SF and SARC-F questionnaires have been shown to be practical and applicable for extensive national epidemiological surveys. Thirdly, the main aspect of this study was to explore overall physical activity levels by calculating the total time spent walking and engaging in moderate to vigorous intensity activities. It categorized these activities according to the WHO’s recommended thresholds for moderate intensity (150–300 min/week) for older adults, which may have underestimated the results for vigorous intensity. However, this study also explored physical activities at both moderate and vigorous intensities separately. Furthermore, this study did not investigate the types of exercises (such as resistance training, aerobic training, etc.) or chronic diseases (such as stroke, diabetes, heart disease, etc.) among older adults, nor did it analyze the association between sedentary behavior and sarcopenia independently. Despite these limitations, this study still provides preliminary insights into physical activity levels exceeding the guidelines in older adults. It suggests possible ways to prevent or decrease the risk of sarcopenia in the future.

The WHO’s global status report on physical activity in 2022 continues to highlight the recommended range of physical activity [45]. Previous related reports have mainly focused on exploring the reduction of physical inactivity, confirming through numerous studies the importance of physical activity in reducing chronic diseases (such as hypertension, diabetes, and heart disease) and proposing related individual physical activity guidelines. In fact, the physical activity levels in many countries have already exceeded the guidelines. However, there is a lack of related research and consistent evidence demonstrating its feasibility. Furthermore, with the aging population trend and the increasing risk of sarcopenia, this issue should also be given attention, and specific physical activity guidelines should be further developed. Therefore, researchers in the future could attempt to use objective scientific measurement methods, such as accelerometers, to accurately analyze the different intensities of physical activity and sedentary behavior in older adults. Additionally, they could further incorporate more potential factors, such as exercise habits, types of exercise, chronic diseases, specific nutrient consumption, muscle mass, muscle strength, and muscle function, to develop a unified assessment method and strategies to prevent and alleviate for sarcopenia in older adults.