In a recent study published in JAMA Network Open, researchers investigated whether reducing sitting time could effectively improve blood pressure (BP) among older adults.

​​​​​​​Study: Sitting Time Reduction and Blood Pressure in Older Adults. Image Credit: insta_photos/Shutterstock.com

Background

Sedentary behavior is associated with adverse health outcomes such as cardiovascular disease, type 2 diabetes, low physical function, and death. Moderate to moderate activity can benefit older adults’ cognitive, physical, functional, and emotional health; however, their compliance with physical activity is poor, with most of them sitting for much of the day.

Identifying modifiable variables is critical to improving cardiometabolic fitness in older individuals. Short-term experimental investigations demonstrate that lowering sitting duration reduces blood pressure, particularly in hypertensive individuals.

About the study

In the present randomized controlled trial, researchers evaluated the impact of sitting time reduction on BP readings in the geriatric population.

The team conducted the Healthy Aging Resources to Thrive (HART) trial primarily remotely at the state level during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic between January 2019 and November 2022.

Participants included adult Kaiser Permanente Washington (KPWA) care recipients, enrolled for at least a year, aged between 60 and 89 years, sitting for ≥6.0 hours daily, and a body mass index (BMI) ranging between 30 and 50 kg/m2.

The researchers excluded palliative, long-term, or hospice care recipients, those with cancer, deafness or considerable hearing impairment, degenerative disorders such as dementia, or adverse mental health conditions in the previous two years, diagnosed using the International Statistical Classification of Diseases and Related Health Problems, tenth revision (ICD-10) codes.

The team randomized the participants in a 1:1 ratio to the sedentary behavior reduction intervention (I-STAND) or healthy living control conditions for six months.

The intervention group received ten health enhancement contacts, sedentary time reduction targets, and a fitness tracker. The controls received ten health training contacts to establish broad healthy living objectives that excluded physical activity and sedentary behavior.

The primary study outcome was sitting duration recorded at study initiation, three months, and six months, using accelerometers for a week at every time point. The researchers monitored systolic BP (SBP) and diastolic BP (DBP) at study initiation and after six months.

The exploratory outcomes included changes in accelerometer standing and walking time, daily step count, number of sitting bouts of ≥30 minutes, mean sitting bouts’ duration, time to perform five chair stands from the Short Physical Performance Battery, and changes in hypertension medication classes.

The researchers performed linear regression modeling for analysis, with study covariates such as age, sex, race, ethnicity, residence county, physical function, retirement status, diabetes, and hypertension.

They also performed a sensitivity analysis, separately analyzing data obtained before and during coronavirus disease 2019 (COVID-19).

Results

The researchers randomized 283 individuals to the I-STAND intervention (n=140) and control (n=143) groups. The mean participant age was 69 years, 186 (66%) were female, and the mean BMI was 35 kg/m2.

At study initiation, 52% (n=147) suffered from hypertension, and 69% (n=97) consumed one or more antihypertensive medications. Accelerometer awake time was nearly 16 hours daily over a week of wear in the study groups.

The team noted sedentary time reduction in favor of the I-STAND intervention, with an average difference of 31 minutes per day at three months and 32 minutes per day at six months.

The intervention group had a considerably higher mean drop in SBP (3.5 mm Hg) after six months. However, DBP changes were not significantly different across the study groups (0.3 mm Hg).

The sensitivity analysis showed similar results. The study found six major adverse events in both the I-STAND intervention group (two cancer diagnoses, one emergency department admission, two hospitalizations, and one fall) and the control group.

However, there were no adverse events associated with the trial. They found no significant intergroup variations in BMI, waist circumference, or body weight.

The study found that standing time rose while sitting bouts’ duration and extended sitting bouts were reduced after six months, favoring the intervention group. Changes in antihypertensive drug classes in both groups were not significant.

Women had significantly lower diastolic blood pressure than men, but the impact was minor. Participants in suburban and rural locations demonstrated minor improvements in diastolic blood pressure, supporting the research intervention.

Conclusion

The study findings revealed that lowering sitting time may be successfully provided remotely, resulting in considerable blood pressure decreases. The intervention, which involved 283 older individuals, decreased sitting duration by >30 minutes per day and SBP by about 3.5 mm Hg.

The findings indicate that sitting time reduction by standing more and taking more frequent breaks may be a unique lifestyle option for decreasing blood pressure that is simpler for older individuals with chronic diseases to implement into their everyday lives.

Possible physiological causes for SBP decreases include frequent interruptions to the bent arterial posture, which may enhance blood flow and vascular shear stress.