Effects of reduced sedentary time on resting, exercise and post-exercise blood pressure in inactive adults with metabolic syndrome – a six-month exploratory RCT

Abstract

Evidence on the long-term effects of reducing sedentary behaviour (SB) on blood pressure (BP) is scarce. Therefore, we performed a sub-analysis of the BP effects of a six-month intervention that aimed at reducing SB by 1 h/day and replacing it with non-exercise activities. Sixty-four physically inactive and sedentary adults with metabolic syndrome (58% female, 58 [SD 7] years, BP 143/88 [16/9] mmHg, SB 10 [1] h/day) were randomised into intervention (INT, n = 33) and control (CON, n = 31) groups. Resting BP and BP at each stage during and after a graded maximal bicycle ergometer test were measured before and after the intervention. SB, standing, moderate-to-vigorous physical activity (MVPA), and light physical activity (LPA) were measured in six-second intervals at baseline and during the whole six-month intervention using hip-worn accelerometers. The analyses were adjusted for BP medication status. The intervention resulted in a 40 min/day reduction in SB and concomitant 20 min/day increase in MVPA. Resting systolic BP was lower in the CON group before and after the intervention. No group x time interactions were observed in resting BP or BP during exercise at submaximal or maximal intensities, or during recovery. The changes in LPA and MVPA were inversely correlated with the changes in BP during light-to-moderate intensity exercise. An intervention that resulted in a 40 min/day reduction in SB for six months was not sufficient at influencing BP at rest, during or after exercise in adults with metabolic syndrome. However, successfully increasing LPA or MVPA might lower BP during light-to-moderate-intensity activities.

Clinical and physiological advances in sedentary behavior research

“…The study flow diagram is presented in Figure 1 . Although the intervention has been completed and findings of one 3-month study and few 6-month studies have been published ( Sjoros et al, 2023a ; Sjoros et al, 2023b ; Norha et al, 2023 ; Norha et al, 2024 ), large part of the 6-month intervention results are still under analysis. These include, but not limited to, insulin sensitivity and other anatomical and physiological research on the brain, liver, heart, adipose tissue, bone and bone marrow, and spinal cord, as well as metabolic flexibility ( Figure 2 ).…”

“… Summary of the results ( Sjoros et al, 2023a ; Sjoros et al, 2023b ; Norha et al, 2023 ; Norha et al, 2024 ) and topics under investigation with regard to the 6-month randomized trial studying the clinical and physiological effects of reduced sitting in metabolic syndrome patients. …”

“…It appears that if sitting is replaced mostly by standing, it is not beneficial for aerobic fitness as standing does not stress the body adequately; alternatively, actual muscle movements are needed, which increases total body energy consumption more substantially and creates the demand for fitness improvement. Furthermore, sedentary behavior reduction did not affect blood pressure at rest or during exercise until maximal exhaustion and recovery from it, but changes in physical activity with the 6-month intervention was associated with reduced blood pressure during corresponding activity levels during the exercise test ( Norha et al, 2024 ). This can be considered beneficial for health and supports the idea of replacing sitting by physical activity for beneficial cardiovascular effects.…”