It is well established that sedentary behavior correlates with a greater risk of age-related disease, higher mortality, and shorter life expectancy. It is tough to prove the direction of causation when using human epidemiological data, however, meaning whether it is the case that exercise is beneficial to health, or, alternatively, that more robust people tend to exercise more. Data from animal studies robustly demonstrates that a lack of exercise is harmful to long-term health, however. It would be surprising for that not to hold up in humans.
As people age, maintaining sufficient physical activity (PA) levels is especially important as physiological decline begins to accelerate after the age of fifty. Sarcopenic changes in the muscle are associated with a decline in resting metabolic rate and glucose metabolism, contributing to increased fat accumulation and insulin resistance. Over time, these changes may negatively affect blood pressure, metabolic function, and overall cardiovascular health. Physical activity has been shown to attenuate the rate and degree to which these cardiometabolic changes occur. However, despite the well-known health benefits of PA, fewer than 30% of adults over the age of 50 engage in the recommended amount of moderate-to-vigorous PA (MVPA).
The high prevalence of sedentary behavior (SB) among older adults is of significant concern as it likely contributes to the minimization of time spent in PA. More than 25% of older adults engage in 6 hours or more of SB daily. Many cardiometabolic outcomes could be improved simply if older adults reduced their SB by increasing the time they spend in light PA (LPA). For many older adults, this is likely a more achievable and realistic goal than increasing time spent in MVPA.
Data was drawn from a convenience sample of 54 community-dwelling individuals (12 males, 42 females; mean age = 72.6 ± 6.8 years). Cardiometabolic biomarkers assessed included systolic blood pressure (SBP) and diastolic blood pressure (DBP), body mass index, waist circumference, and fasting blood glucose and cholesterol parameters. SB was assessed via accelerometry over a 7-day period, and measures included daily time in SB, number and length of sedentary bouts, the number and length of breaks between sedentary bouts, moderate-to-vigorous physical activity (MVPA), and light physical activity (LPA).
Adjusted regression analyses showed that daily sedentary time was positively associated with DBP and inversely associated with HDL cholesterol. Sedentary bout length was also associated with DBP and HDL cholesterol. Replacement of 10 minutes of SB a day with LPA was associated with improved DBP and HDL cholesterol. In conclusion, sitting for prolonged periods of time without interruption is unfavorably associated with DBP and HDL cholesterol.