Background Sarcopenic obesity describes the age-associated loss of skeletal muscle mass and function coupled with high levels of adiposity. Co-existence of sarcopenia and obesity may heighten effects on physical function, disability and mortality. Physical activity (PA) is a modifiable risk factor that may protect against the onset of sarcopenia and sarcopenic obesity. We investigated associations between different intensities of objectively measured PA with sarcopenia and sarcopenic obesity in older British men.

Methods The British Regional Heart Study, a prospective cohort study, recruited 7735 men from 24 British towns in 1978–80. In 2010–12, survivors (aged 70–92 years) attended a follow up with physical measurements. Sarcopenia was defined as low muscle mass (lowest two fifths of the mid-upper arm muscle circumference distribution) accompanied by either low muscular strength (hand grip strength <30 kg measured by dynamometer) or low physical performance (gait speed ≤ 0.8 m/s measured by timed 3-metre walk); severe sarcopenia was based on presence of all three conditions. Sarcopenic obesity was defined as sarcopenia or severe sarcopenia and a waist circumference of >102 cm. Men wore a GT3x accelerometer over the hip for 7 days and reported participation in strength training. Multinomial regression models were used for cross-sectional analyses relating PA and sarcopenia.

Results 1286/3137 (41%) surviving participants aged 78.2 years (SD = 4.5) had complete covariate and PA data. 14.2% (n = 183) had sarcopenia and a further 5.4% (n = 70) had severe sarcopenia. 25.3% of sarcopenic or severely sarcopenic men were obese. Each extra 30 minutes/day of moderate-to-vigorous PA (MVPA) was associated with a reduced risk of severe sarcopenia (adjusted relative risk [RR] 0.57, 95% confidence interval [CI] 0.32, 1.00) and sarcopenic obesity (RR 0.47 [95% CI 0.27, 0.84]). Each additional 1000 steps/day was associated with RR 0.79 [95% CI 0.68, 0.93]) for severe sarcopenia and RR 0.68 [95% CI 0.58, 0.79] for sarcopenic obesity. Light PA (LPA) and sedentary breaks were marginally associated with a reduced risk of sarcopenic obesity. Each extra 30 minutes/day of sedentary time was associated with a slightly increased risk of sarcopenic obesity independent of MVPA (RR 1.18 [95% CI 0.99, 1.40]). Participation in strength training was associated with reduced risks of sarcopenic non-obese compared to non-sarcopenic non-obese (RR 0.52 [95% CI 0.26, 1.03]).

Conclusion Regular MVPA may help reduce risk of severe sarcopenia and sarcopenic obesity. Reducing sedentary time and increasing LPA and sedentary breaks may also protect against sarcopenic obesity. Further larger studies with a longitudinal design are required to determine causality.